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SL Paper 2

A water container is made in the shape of a cylinder with internal height h cm and internal base radius r cm.

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The water container has no top. The inner surfaces of the container are to be coated with a water-resistant material.

The volume of the water container is 0.5   m 3 .

The water container is designed so that the area to be coated is minimized.

One can of water-resistant material coats a surface area of 2000  c m 2 .

Write down a formula for A , the surface area to be coated.

[2]
a.

Express this volume in  c m 3 .

[1]
b.

Write down, in terms of r and h , an equation for the volume of this water container.

[1]
c.

Show that A = π r 2 + 1 000 000 r .

[2]
d.

Find d A d r .

[3]
e.

Using your answer to part (e), find the value of r which minimizes A .

[3]
f.

Find the value of this minimum area.

[2]
g.

Find the least number of cans of water-resistant material that will coat the area in part (g).

[3]
h.



The following table shows a probability distribution for the random variable X , where E ( X ) = 1.2 .

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A bag contains white and blue marbles, with at least three of each colour. Three marbles are drawn from the bag, without replacement. The number of blue marbles drawn is given by the random variable X .

A game is played in which three marbles are drawn from the bag of ten marbles, without replacement. A player wins a prize if three white marbles are drawn.

Find q .

[2]
a.i.

Find p .

[2]
a.ii.

Write down the probability of drawing three blue marbles.

[1]
b.i.

Explain why the probability of drawing three white marbles is 1 6 .

[1]
b.ii.

The bag contains a total of ten marbles of which w are white. Find w .

[3]
b.iii.

Jill plays the game nine times. Find the probability that she wins exactly two prizes.

[2]
c.

Grant plays the game until he wins two prizes. Find the probability that he wins his second prize on his eighth attempt.

[4]
d.



The following table shows the probability distribution of a discrete random variable X , where  a 0 and  b 0 .

Show that  b = 0.3 a .

[1]
a.

Find the difference between the greatest possible expected value and the least possible expected value.

[6]
b.



The time it takes Suzi to drive from home to work each morning is normally distributed with a mean of 35 minutes and a standard deviation of σ minutes.

On 25% of days, it takes Suzi longer than 40 minutes to drive to work.

Suzi will be late to work if it takes her longer than 45 minutes to drive to work. The time it takes to drive to work each day is independent of any other day.

Suzi will work five days next week.

Suzi will work 22 days this month. She will receive a bonus if she is on time at least 20 of those days.

So far this month, she has worked 16 days and been on time 15 of those days.

Find the value of σ.

[4]
a.

On a randomly selected day, find the probability that Suzi’s drive to work will take longer than 45 minutes.

[2]
b.

Find the probability that she will be late to work at least one day next week.

[3]
c.

Given that Suzi will be late to work at least one day next week, find the probability that she will be late less than three times.

[5]
d.

Find the probability that Suzi will receive a bonus.

[4]
e.



The following table shows values of ln x and ln y.

The relationship between ln x and ln y can be modelled by the regression equation ln y = a ln x + b.

Find the value of a and of b.

[3]
a.

Use the regression equation to estimate the value of y when x = 3.57.

[3]
b.

The relationship between x and y can be modelled using the formula y = kxn, where k ≠ 0 , n ≠ 0 , n ≠ 1.

By expressing ln y in terms of ln x, find the value of n and of k.

[7]
c.



In a group of 35 students, some take art class (A) and some take music class (M). 5 of these students do not take either class. This information is shown in the following Venn diagram.

One student from the group is chosen at random. Find the probability that

Write down the number of students in the group who take art class.

[2]
a.

the student does not take art class.

[2]
b.i.

the student takes either art class or music class, but not both.

[2]
b.ii.



The marks obtained by nine Mathematical Studies SL students in their projects (x) and their final IB examination scores (y) were recorded. These data were used to determine whether the project mark is a good predictor of the examination score. The results are shown in the table.

The equation of the regression line y on x is y = mx + c.

A tenth student, Jerome, obtained a project mark of 17.

Use your graphic display calculator to write down x ¯ , the mean project mark.

[1]
a.i.

Use your graphic display calculator to write down y ¯ , the mean examination score.

[1]
a.ii.

Use your graphic display calculator to write down r , Pearson’s product–moment correlation coefficient.

[2]
a.iii.

Find the exact value of m and of c for these data.

[2]
b.i.

Show that the point M ( x ¯ , y ¯ ) lies on the regression line y on x.

[2]
b.ii.

Use the regression line y on x to estimate Jerome’s examination score.

[2]
c.i.

Justify whether it is valid to use the regression line y on x to estimate Jerome’s examination score.

[2]
c.ii.

In his final IB examination Jerome scored 65.

Calculate the percentage error in Jerome’s estimated examination score.

[2]
d.



Emlyn plays many games of basketball for his school team. The number of minutes he plays in each game follows a normal distribution with mean m minutes.

In any game there is a 30% chance he will play less than 13.6 minutes.

In any game there is a 70% chance he will play less than 17.8 minutes.

The standard deviation of the number of minutes Emlyn plays in any game is 4.

There is a 60% chance Emlyn plays less than x minutes in a game.

Emlyn will play in two basketball games today.

Emlyn and his teammate Johan each practise shooting the basketball multiple times from a point X. A record of their performance over the weekend is shown in the table below.

On Monday, Emlyn and Johan will practise and each will shoot 200 times from point X.

Sketch a diagram to represent this information.

[2]
a.

Show that m=15.7.

[2]
b.

Find the probability that Emlyn plays between 13 minutes and 18 minutes in a game.

[2]
c.i.

Find the probability that Emlyn plays more than 20 minutes in a game.

[2]
c.ii.

Find the value of x.

[2]
d.

Find the probability he plays between 13 minutes and 18 minutes in one game and more than 20 minutes in the other game.

[3]
e.

Find the expected number of successful shots Emlyn will make on Monday, based on the results from Saturday and Sunday.

[2]
f.

Emlyn claims the results from Saturday and Sunday show that his expected number of successful shots will be more than Johan’s.

Determine if Emlyn’s claim is correct. Justify your reasoning.

[2]
g.



On a school excursion, 100 students visited an amusement park. The amusement park’s main attractions are rollercoasters (R), water slides (W), and virtual reality rides (V).

The students were asked which main attractions they visited. The results are shown in the Venn diagram.

A total of 74 students visited the rollercoasters or the water slides.

Find the value of a.

[2]
a.i.

Find the value of b.

[2]
a.ii.

Find the number of students who visited at least two types of main attraction.

[2]
b.

Write down the value of n( RW) .

[1]
c.

Find the probability that a randomly selected student visited the rollercoasters.

[2]
d.i.

Find the probability that a randomly selected student visited the virtual reality rides.

[1]
d.ii.

Hence determine whether the events in parts (d)(i) and (d)(ii) are independent. Justify your reasoning. 

[2]
e.



At a school, 70% of the students play a sport and 20% of the students are involved in theatre. 18% of the students do neither activity.

A student is selected at random.

At the school 48% of the students are girls, and 25% of the girls are involved in theatre.

A student is selected at random. Let G be the event “the student is a girl” and let T be the event “the student is involved in theatre”.

Find the probability that the student plays a sport and is involved in theatre.

[2]
a.

Find the probability that the student is involved in theatre, but does not play a sport.

[2]
b.

Find PGT.

[2]
c.

Determine if the events G and T are independent. Justify your answer.

[2]
d.



The heights of adult males in a country are normally distributed with a mean of 180 cm and a standard deviation of σ  cm . 17% of these men are shorter than 168 cm. 80% of them have heights between ( 192 h )  cm and 192 cm.

Find the value of h .




The following table shows the average body weight, x , and the average weight of the brain, y , of seven species of mammal. Both measured in kilograms (kg).

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The average body weight of grey wolves is 36 kg.

In fact, the average weight of the brain of grey wolves is 0.120 kg.

The average body weight of mice is 0.023 kg.

Find the range of the average body weights for these seven species of mammal.

[2]
a.

For the data from these seven species calculate r , the Pearson’s product–moment correlation coefficient;

[2]
b.i.

For the data from these seven species describe the correlation between the average body weight and the average weight of the brain.

[2]
b.ii.

Write down the equation of the regression line y on x , in the form y = m x + c .

[2]
c.

Use your regression line to estimate the average weight of the brain of grey wolves.

[2]
d.

Find the percentage error in your estimate in part (d).

[2]
e.

State whether it is valid to use the regression line to estimate the average weight of the brain of mice. Give a reason for your answer.

[2]
f.



At Penna Airport the probability, P(A), that all passengers arrive on time for a flight is 0.70. The probability, P(D), that a flight departs on time is 0.85. The probability that all passengers arrive on time for a flight and it departs on time is 0.65.

The number of hours that pilots fly per week is normally distributed with a mean of 25 hours and a standard deviation σ . 90 % of pilots fly less than 28 hours in a week.

Show that event A and event D are not independent.

[2]
a.

Find P ( A D ) .

[2]
b.i.

 Given that all passengers for a flight arrive on time, find the probability that the flight does not depart on time.

[3]
b.ii.

Find the value of σ .

[3]
c.

All flights have two pilots. Find the percentage of flights where both pilots flew more than 30 hours last week.

[4]
d.



The table below shows the distribution of test grades for 50 IB students at Greendale School.

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A student is chosen at random from these 50 students.

A second student is chosen at random from these 50 students.

The number of minutes that the 50 students spent preparing for the test was normally distributed with a mean of 105 minutes and a standard deviation of 20 minutes.

Calculate the mean test grade of the students;

[2]
a.i.

Calculate the standard deviation.

[1]
a.ii.

Find the median test grade of the students.

[1]
b.

Find the interquartile range.

[2]
c.

Find the probability that this student scored a grade 5 or higher.

[2]
d.

Given that the first student chosen at random scored a grade 5 or higher, find the probability that both students scored a grade 6.

[3]
e.

Calculate the probability that a student chosen at random spent at least 90 minutes preparing for the test.

[2]
f.i.

Calculate the expected number of students that spent at least 90 minutes preparing for the test.

[2]
f.ii.



In the month before their IB Diploma examinations, eight male students recorded the number of hours they spent on social media.

For each student, the number of hours spent on social media ( x ) and the number of IB Diploma points obtained ( y ) are shown in the following table.

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Use your graphic display calculator to find

Ten female students also recorded the number of hours they spent on social media in the month before their IB Diploma examinations. Each of these female students spent between 3 and 30 hours on social media.

The equation of the regression line y on x for these ten female students is

y = 2 3 x + 125 3 .

An eleventh girl spent 34 hours on social media in the month before her IB Diploma examinations.

On graph paper, draw a scatter diagram for these data. Use a scale of 2 cm to represent 5 hours on the x -axis and 2 cm to represent 10 points on the y -axis.

[4]
a.

(i)     x ¯ , the mean number of hours spent on social media;

(ii)     y ¯ , the mean number of IB Diploma points.

[2]
b.

Plot the point ( x ¯ ,   y ¯ )  on your scatter diagram and label this point M.

[2]
c.

Write down the value of r , the Pearson’s product–moment correlation coefficient, for these data.

[2]
d.

Write down the equation of the regression line y on x for these eight male students.

[2]
e.

Draw the regression line, from part (e), on your scatter diagram.

[2]
f.

Use the given equation of the regression line to estimate the number of IB Diploma points that this girl obtained.

[2]
g.

Write down a reason why this estimate is not reliable.

[1]
h.



A manufacturer produces 1500 boxes of breakfast cereal every day.

The weights of these boxes are normally distributed with a mean of 502 grams and a standard deviation of 2 grams.

All boxes of cereal with a weight between 497.5 grams and 505 grams are sold. The manufacturer’s income from the sale of each box of cereal is $2.00.

The manufacturer recycles any box of cereal with a weight not between 497.5 grams and 505 grams. The manufacturer’s recycling cost is $0.16 per box.

A different manufacturer produces boxes of cereal with weights that are normally distributed with a mean of 350 grams and a standard deviation of 1.8 grams.

This manufacturer sells all boxes of cereal that are above a minimum weight, w .

They sell 97% of the cereal boxes produced.

Draw a diagram that shows this information.

[2]
a.

(i)     Find the probability that a box of cereal, chosen at random, is sold.

(ii)     Calculate the manufacturer’s expected daily income from these sales.

[4]
b.

Calculate the manufacturer’s expected daily recycling cost.

[2]
c.

Calculate the value of w .

[3]
d.



The final examination results obtained by a group of 3200 Biology students are summarized on the cumulative frequency graph.

350 of the group obtained the highest possible grade in the examination.

The grouped frequency table summarizes the examination results of this group of students.

Find the median of the examination results.

[2]
a.i.

Find the interquartile range.

[3]
a.ii.

Find the final examination result required to obtain the highest possible grade.

[2]
b.

Write down the modal class.

[2]
c.i.

Write down the mid-interval value of the modal class.

[1]
c.ii.

Calculate an estimate of the mean examination result.

[2]
d.i.

Calculate an estimate of the standard deviation, giving your answer correct to three decimal places.

[1]
d.ii.

The teacher sets a grade boundary that is one standard deviation below the mean.

Use the cumulative frequency graph to estimate the number of students whose final examination result was below this grade boundary.

[3]
e.



A company performs an experiment on the efficiency of a liquid that is used to detect a nut allergy.

A group of 60 people took part in the experiment. In this group 26 are allergic to nuts. One person from the group is chosen at random.

A second person is chosen from the group.

When the liquid is added to a person’s blood sample, it is expected to turn blue if the person is allergic to nuts and to turn red if the person is not allergic to nuts.

The company claims that the probability that the test result is correct is 98% for people who are allergic to nuts and 95% for people who are not allergic to nuts.

It is known that 6 in every 1000 adults are allergic to nuts.

This information can be represented in a tree diagram.

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An adult, who was not part of the original group of 60, is chosen at random and tested using this liquid.

The liquid is used in an office to identify employees who might be allergic to nuts. The liquid turned blue for 38 employees.

Find the probability that both people chosen are not allergic to nuts.

[2]
b.

Copy and complete the tree diagram.

[3]
c.

Find the probability that this adult is allergic to nuts and the liquid turns blue.

[2]
d.

Find the probability that the liquid turns blue.

[3]
e.

Find the probability that the tested adult is allergic to nuts given that the liquid turned blue.

[3]
f.

Estimate the number of employees, from this 38, who are allergic to nuts.

[2]
g.



In a company it is found that 25 % of the employees encountered traffic on their way to work. From those who encountered traffic the probability of being late for work is 80 %.

From those who did not encounter traffic, the probability of being late for work is 15 %.

The tree diagram illustrates the information.

The company investigates the different means of transport used by their employees in the past year to travel to work. It was found that the three most common means of transport used to travel to work were public transportation (P ), car (C ) and bicycle (B ).

The company finds that 20 employees travelled by car, 28 travelled by bicycle and 19 travelled by public transportation in the last year.

Some of the information is shown in the Venn diagram.

There are 54 employees in the company.

Write down the value of a.

[1]
a.i.

Write down the value of b.

[1]
a.ii.

Use the tree diagram to find the probability that an employee encountered traffic and was late for work.

[2]
b.i.

Use the tree diagram to find the probability that an employee was late for work.

[3]
b.ii.

Use the tree diagram to find the probability that an employee encountered traffic given that they were late for work.

[3]
b.iii.

Find the value of x.

[1]
c.i.

Find the value of y.

[1]
c.ii.

Find the number of employees who, in the last year, did not travel to work by car, bicycle or public transportation.

[2]
d.

Find  n ( ( C B ) P ) .

[2]
e.



Adam is a beekeeper who collected data about monthly honey production in his bee hives. The data for six of his hives is shown in the following table.

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The relationship between the variables is modelled by the regression line with equation P = a N + b .

Adam has 200 hives in total. He collects data on the monthly honey production of all the hives. This data is shown in the following cumulative frequency graph.

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Adam’s hives are labelled as low, regular or high production, as defined in the following table.

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Adam knows that 128 of his hives have a regular production.

Write down the value of a and of b .

[3]
a.

Use this regression line to estimate the monthly honey production from a hive that has 270 bees.

[2]
b.

Write down the number of low production hives.

[1]
c.

Find the value of k ;

[3]
d.i.

Find the number of hives that have a high production.

[2]
d.ii.

Adam decides to increase the number of bees in each low production hive. Research suggests that there is a probability of 0.75 that a low production hive becomes a regular production hive. Calculate the probability that 30 low production hives become regular production hives.

[3]
e.



Consider the following frequency table.

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Write down the mode.

[1]
a.i.

Find the value of the range.

[2]
a.ii.

Find the mean.

[2]
b.i.

Find the variance.

[2]
b.ii.



The weights, in grams, of oranges grown in an orchard, are normally distributed with a mean of 297 g. It is known that 79 % of the oranges weigh more than 289 g and 9.5 % of the oranges weigh more than 310 g.

The weights of the oranges have a standard deviation of σ.

The grocer at a local grocery store will buy the oranges whose weights exceed the 35th percentile.

The orchard packs oranges in boxes of 36.

Find the probability that an orange weighs between 289 g and 310 g.

[2]
a.

Find the standardized value for 289 g.

[2]
b.i.

Hence, find the value of σ.

[3]
b.ii.

To the nearest gram, find the minimum weight of an orange that the grocer will buy.

[3]
c.

Find the probability that the grocer buys more than half the oranges in a box selected at random.

[5]
d.

The grocer selects two boxes at random.

Find the probability that the grocer buys more than half the oranges in each box.

[2]
e.



A factory manufactures lamps. It is known that the probability that a lamp is found to be defective is 0.05. A random sample of 30 lamps is tested.

Find the probability that there is at least one defective lamp in the sample.

[3]
a.

Given that there is at least one defective lamp in the sample, find the probability that there are at most two defective lamps.

[4]
b.



The weight, W, of basketball players in a tournament is found to be normally distributed with a mean of 65 kg and a standard deviation of 5 kg.

The probability that a basketball player has a weight that is within 1.5 standard deviations of the mean is q.

A basketball coach observed 60 of her players to determine whether their performance and their weight were independent of each other. Her observations were recorded as shown in the table.

She decided to conduct a χ 2 test for independence at the 5% significance level.

Find the probability that a basketball player has a weight that is less than 61 kg.

[2]
a.i.

In a training session there are 40 basketball players.

Find the expected number of players with a weight less than 61 kg in this training session.

[2]
a.ii.

Sketch a normal curve to represent this probability.

[2]
b.i.

Find the value of q.

[1]
b.ii.

Given that P(W > k) = 0.225 , find the value of k.

[2]
c.

For this test state the null hypothesis.

[1]
d.i.

For this test find the p-value.

[2]
d.ii.

State a conclusion for this test. Justify your answer.

[2]
e.



The weights, W , of newborn babies in Australia are normally distributed with a mean 3.41 kg and standard deviation 0.57 kg. A newborn baby has a low birth weight if it weighs less than w kg.

Given that 5.3% of newborn babies have a low birth weight, find w .




160 students attend a dual language school in which the students are taught only in Spanish or taught only in English.

A survey was conducted in order to analyse the number of students studying Biology or Mathematics. The results are shown in the Venn diagram.

 

Set S represents those students who are taught in Spanish.

Set B represents those students who study Biology.

Set M represents those students who study Mathematics.

 

A student from the school is chosen at random.

Find the number of students in the school that are taught in Spanish.

[2]
a.i.

Find the number of students in the school that study Mathematics in English.

[2]
a.ii.

Find the number of students in the school that study both Biology and Mathematics.

[2]
a.iii.

Write down  n ( S ( M B ) ) .

[1]
b.i.

Write down n ( B M S ) .

[1]
b.ii.

Find the probability that this student studies Mathematics.

[2]
c.i.

Find the probability that this student studies neither Biology nor Mathematics.

[2]
c.ii.

Find the probability that this student is taught in Spanish, given that the student studies Biology.

[2]
c.iii.



Lucy sells hot chocolate drinks at her snack bar and has noticed that she sells more hot chocolates on cooler days. On six different days, she records the maximum daily temperature, T, measured in degrees centigrade, and the number of hot chocolates sold, H. The results are shown in the following table.

The relationship between H and T can be modelled by the regression line with equation H=aT+b.

Find the value of a and of b.

[3]
a.i.

Write down the correlation coefficient.

[1]
a.ii.

Using the regression equation, estimate the number of hot chocolates that Lucy will sell on a day when the maximum temperature is 12°C.

[2]
b.



Let A and B be two independent events such that P(AB')=0.16 and P(AB)=0.36.

Given that P(AB)=x, find the value of x.

[4]
a.

Find PA'B'.

[2]
b.



The time, T minutes, taken to complete a jigsaw puzzle can be modelled by a normal distribution with mean μ and standard deviation 8.6.

It is found that 30% of times taken to complete the jigsaw puzzle are longer than 36.8 minutes.

Use μ=32.29 in the remainder of the question.

Six randomly chosen people complete the jigsaw puzzle.

By stating and solving an appropriate equation, show, correct to two decimal places, that μ=32.29.

[4]
a.

Find the 86th percentile time to complete the jigsaw puzzle.

[2]
b.

Find the probability that a randomly chosen person will take more than 30 minutes to complete the jigsaw puzzle.

[2]
c.

Find the probability that at least five of them will take more than 30 minutes to complete the jigsaw puzzle.

[3]
d.

Having spent 25 minutes attempting the jigsaw puzzle, a randomly chosen person had not yet completed the puzzle.

Find the probability that this person will take more than 30 minutes to complete the jigsaw puzzle.

[4]
e.



All answers in this question should be given to four significant figures.


In a local weekly lottery, tickets cost $2 each.

In the first week of the lottery, a player will receive $D for each ticket, with the probability distribution shown in the following table. For example, the probability of a player receiving $10 is 0.03. The grand prize in the first week of the lottery is $1000.

If nobody wins the grand prize in the first week, the probabilities will remain the same, but the value of the grand prize will be $2000 in the second week, and the value of the grand prize will continue to double each week until it is won. All other prize amounts will remain the same.

Find the value of c.

[2]
a.

Determine whether this lottery is a fair game in the first week. Justify your answer.

[4]
b.

Given that the grand prize is not won and the grand prize continues to double, write an expression in terms of n for the value of the grand prize in the nth week of the lottery.

[2]
c.

The wth week is the first week in which the player is expected to make a profit. Ryan knows that if he buys a lottery ticket in the wth week, his expected profit is $p.

Find the value of p.

[7]
d.



On one day 180 flights arrived at a particular airport. The distance travelled and the arrival status for each incoming flight was recorded. The flight was then classified as on time, slightly delayed, or heavily delayed.

The results are shown in the following table.

A χ2 test is carried out at the 10 % significance level to determine whether the arrival status of incoming flights is independent of the distance travelled.

The critical value for this test is 7.779.

A flight is chosen at random from the 180 recorded flights.

State the alternative hypothesis.

[1]
a.

Calculate the expected frequency of flights travelling at most 500 km and arriving slightly delayed.

[2]
b.

Write down the number of degrees of freedom.

[1]
c.

Write down the χ2 statistic.

[2]
d.i.

Write down the associated p-value.

[1]
d.ii.

State, with a reason, whether you would reject the null hypothesis.

[2]
e.

Write down the probability that this flight arrived on time.

[2]
f.

Given that this flight was not heavily delayed, find the probability that it travelled between 500 km and 5000 km.

[2]
g.

Two flights are chosen at random from those which were slightly delayed.

Find the probability that each of these flights travelled at least 5000 km.

[3]
h.



The flight times, T minutes, between two cities can be modelled by a normal distribution with a mean of 75 minutes and a standard deviation of σ minutes.

On a particular day, there are 64 flights scheduled between these two cities.

Given that 2% of the flight times are longer than 82 minutes, find the value of σ.

[3]
a.

Find the probability that a randomly selected flight will have a flight time of more than 80 minutes.

[2]
b.

Given that a flight between the two cities takes longer than 80 minutes, find the probability that it takes less than 82 minutes.

[4]
c.

Find the expected number of flights that will have a flight time of more than 80 minutes.

[3]
d.

Find the probability that more than 6 of the flights on this particular day will have a flight time of more than 80 minutes.

[3]
e.



The following table shows the data collected from an experiment.

The data is also represented on the following scatter diagram.

The relationship between x and y can be modelled by the regression line of y on x with equation y=ax+b, where a, b.

Write down the value of a and the value of b.

[2]
a.

Use this model to predict the value of y when x=18.

[2]
b.

Write down the value of x¯ and the value of y¯.

[1]
c.

Draw the line of best fit on the scatter diagram.

[2]
d.



At a café, the waiting time between ordering and receiving a cup of coffee is dependent upon the number of customers who have already ordered their coffee and are waiting to receive it.

Sarah, a regular customer, visited the café on five consecutive days. The following table shows the number of customers, x, ahead of Sarah who have already ordered and are waiting to receive their coffee and Sarah’s waiting time, y minutes.

The relationship between x and y can be modelled by the regression line of y on x with equation y=ax+b.

Find the value of a and the value of b.

[2]
a.i.

Write down the value of Pearson’s product-moment correlation coefficient, r.

[1]
a.ii.

Interpret, in context, the value of a found in part (a)(i).

[1]
b.

On another day, Sarah visits the café to order a coffee. Seven customers have already ordered their coffee and are waiting to receive it.

Use the result from part (a)(i) to estimate Sarah’s waiting time to receive her coffee.

[2]
c.



The number of hours spent exercising each week by a group of students is shown in the following table.

The median is 4.5 hours.

Find the value of x.

[2]
a.

Find the standard deviation.

[2]
b.



Sila High School has 110 students. They each take exactly one language class from a choice of English, Spanish or Chinese. The following table shows the number of female and male students in the three different language classes.

A χ 2  test was carried out at the 5 % significance level to analyse the relationship between gender and student choice of language class.

Use your graphic display calculator to write down

The critical value at the 5 % significance level for this test is 5.99.

One student is chosen at random from this school.

Another student is chosen at random from this school.

Write down the null hypothesis, H, for this test.

[1]
a.

State the number of degrees of freedom.

[1]
b.

the expected frequency of female students who chose to take the Chinese class.

[1]
c.i.

the χ 2 statistic.

[2]
c.ii.

State whether or not H0 should be rejected. Justify your statement.

[2]
d.

Find the probability that the student does not take the Spanish class.

[2]
e.i.

Find the probability that neither of the two students take the Spanish class.

[3]
e.ii.

Find the probability that at least one of the two students is female.

[3]
e.iii.



The manager of a folder factory recorded the number of folders produced by the factory (in thousands) and the production costs (in thousand Euros), for six consecutive months.

M17/5/MATSD/SP2/ENG/TZ2/03

Every month the factory sells all the folders produced. Each folder is sold for 2.99 Euros.

Draw a scatter diagram for this data. Use a scale of 2 cm for 5000 folders on the horizontal axis and 2 cm for 10 000 Euros on the vertical axis.

[4]
a.

Write down, for this set of data the mean number of folders produced, x ¯ ;

[1]
b.i.

Write down, for this set of data the mean production cost, C ¯ .

[1]
b.ii.

Label the point M ( x ¯ ,   C ¯ ) on the scatter diagram.

[1]
c.

Use your graphic display calculator to find the Pearson’s product–moment correlation coefficient, r .

[2]
d.

State a reason why the regression line C on x is appropriate to model the relationship between these variables.

[1]
e.

Use your graphic display calculator to find the equation of the regression line C on x .

[2]
f.

Draw the regression line C on x on the scatter diagram.

[2]
g.

Use the equation of the regression line to estimate the least number of folders that the factory needs to sell in a month to exceed its production cost for that month.

[4]
h.



A biased four-sided die is rolled. The following table gives the probability of each score.

Find the value of k.

[2]
a.

Calculate the expected value of the score.

[2]
b.

The die is rolled 80 times. On how many rolls would you expect to obtain a three?

[2]
c.



The following table shows the hand lengths and the heights of five athletes on a sports team.

The relationship between x and y can be modelled by the regression line with equation y = ax + b.

Find the value of a and of b.

[3]
a.i.

Write down the correlation coefficient.

[1]
a.ii.

Another athlete on this sports team has a hand length of 21.5 cm. Use the regression equation to estimate the height of this athlete.

[2]
b.



A survey was conducted on a group of people. The first question asked how many pets they each own. The results are summarized in the following table.

The second question asked each member of the group to state their age and preferred pet. The data obtained is organized in the following table.

A χ 2 test is carried out at the 10 % significance level.

Write down the total number of people, from this group, who are pet owners.

[1]
a.

Write down the modal number of pets.

[1]
b.

For these data, write down the median number of pets.

[1]
c.i.

For these data, write down the lower quartile.

[1]
c.ii.

For these data, write down the upper quartile.

[1]
c.iii.

Write down the ratio of teenagers to non-teenagers in its simplest form.

[1]
d.

State the null hypothesis.

[1]
e.i.

State the alternative hypothesis.

[1]
e.ii.

Write down the number of degrees of freedom for this test.

[1]
f.

Calculate the expected number of teenagers that prefer cats.

[2]
g.

Use your graphic display calculator to find the p -value for this test.

[2]
h.

State the conclusion for this test. Give a reason for your answer.

[2]
i.



A transportation company owns 30 buses. The distance that each bus has travelled since being purchased by the company is recorded. The cumulative frequency curve for these data is shown.

It is known that 8 buses travelled more than m kilometres.

Find the number of buses that travelled a distance between 15000 and 20000 kilometres.

[2]
a.

Use the cumulative frequency curve to find the median distance.

[2]
b.i.

Use the cumulative frequency curve to find the lower quartile.

[1]
b.ii.

Use the cumulative frequency curve to find the upper quartile.

[1]
b.iii.

Hence write down the interquartile range.

[1]
c.

Write down the percentage of buses that travelled a distance greater than the upper quartile.

[1]
d.

Find the number of buses that travelled a distance less than or equal to 12 000 km.

[1]
e.

Find the value of m.

[2]
f.

The smallest distance travelled by one of the buses was 2500 km.
The longest distance travelled by one of the buses was 23 000 km.

On graph paper, draw a box-and-whisker diagram for these data. Use a scale of 2 cm to represent 5000 km.

[4]
g.



The random variable X follows a normal distribution with mean μ and standard deviation σ.

The avocados grown on a farm have weights, in grams, that are normally distributed with mean μ and standard deviation σ. Avocados are categorized as small, medium, large or premium, according to their weight. The following table shows the probability an avocado grown on the farm is classified as small, medium, large or premium.

The maximum weight of a small avocado is 106.2 grams.

The minimum weight of a premium avocado is 182.6 grams.

A supermarket purchases all the avocados from the farm that weigh more than 106.2 grams.

Find the probability that an avocado chosen at random from this purchase is categorized as

Find Pμ-1.5σ<X<μ+1.5σ.

[3]
a.

Find the value of μ and of σ.

[5]
b.

medium.

[2]
c.i.

large.

[1]
c.ii.

premium.

[1]
c.iii.

The selling prices of the different categories of avocado at this supermarket are shown in the following table:

 

 

 

 

The supermarket pays the farm $200 for the avocados and assumes it will then sell them in exactly the same proportion as purchased from the farm.

According to this model, find the minimum number of avocados that must be sold so that the net profit for the supermarket is at least $438.

[4]
d.



Fiona walks from her house to a bus stop where she gets a bus to school. Her time, W minutes, to walk to the bus stop is normally distributed with W~N12, 32.

Fiona always leaves her house at 07:15. The first bus that she can get departs at 07:30.

The length of time, B minutes, of the bus journey to Fiona’s school is normally distributed with B~N50, σ2. The probability that the bus journey takes less than 60 minutes is 0.941.

If Fiona misses the first bus, there is a second bus which departs at 07:45. She must arrive at school by 08:30 to be on time. Fiona will not arrive on time if she misses both buses. The variables W and B are independent.

Find the probability that it will take Fiona between 15 minutes and 30 minutes to walk to the bus stop.

[2]
a.

Find σ.

[3]
b.

Find the probability that the bus journey takes less than 45 minutes.

[2]
c.

Find the probability that Fiona will arrive on time.

[5]
d.

This year, Fiona will go to school on 183 days.

Calculate the number of days Fiona is expected to arrive on time.

[2]
e.



Let f ( x ) = 0.5 x 4 + 3 x 2 + 2 x . The following diagram shows part of the graph of f .

M17/5/MATME/SP2/ENG/TZ2/08

 

There are x -intercepts at x = 0 and at x = p . There is a maximum at A where x = a , and a point of inflexion at B where x = b .

Find the value of p .

[2]
a.

Write down the coordinates of A.

[2]
b.i.

Write down the rate of change of f  at A.

[1]
b.ii.

Find the coordinates of B.

[4]
c.i.

Find the the rate of change of f at B.

[3]
c.ii.

Let R be the region enclosed by the graph of f , the x -axis, the line x = b and the line x = a . The region R is rotated 360° about the x -axis. Find the volume of the solid formed.

[3]
d.



A group of 7 adult men wanted to see if there was a relationship between their Body Mass Index (BMI) and their waist size. Their waist sizes, in centimetres, were recorded and their BMI calculated. The following table shows the results.

The relationship between x and y can be modelled by the regression equation y = a x + b .

Write down the value of a and of b .

[3]
a.i.

Find the correlation coefficient.

[1]
a.ii.

Use the regression equation to estimate the BMI of an adult man whose waist size is 95 cm.

[2]
b.



A company produces bags of sugar whose masses, in grams, can be modelled by a normal distribution with mean 1000 and standard deviation 3.5. A bag of sugar is rejected for sale if its mass is less than 995 grams.

Find the probability that a bag selected at random is rejected.

[2]
a.

Estimate the number of bags which will be rejected from a random sample of 100 bags.

[1]
b.

Given that a bag is not rejected, find the probability that it has a mass greater than 1005 grams.

[3]
c.



There are three fair six-sided dice. Each die has two green faces, two yellow faces and two red faces.

All three dice are rolled.

Ted plays a game using these dice. The rules are:

The random variable D  ($) represents how much is added to his winnings after a turn.

The following table shows the distribution for D , where $ w represents his winnings in the game so far.

Find the probability of rolling exactly one red face.

[2]
a.i.

Find the probability of rolling two or more red faces.

[3]
a.ii.

Show that, after a turn, the probability that Ted adds exactly $10 to his winnings is  1 3 .

[5]
b.

Write down the value of x .

[1]
c.i.

Hence, find the value of y .

[2]
c.ii.

Ted will always have another turn if he expects an increase to his winnings.

Find the least value of w for which Ted should end the game instead of having another turn.

[3]
d.



The length, X mm, of a certain species of seashell is normally distributed with mean 25 and variance, σ 2 .

The probability that X is less than 24.15 is 0.1446.

A random sample of 10 seashells is collected on a beach. Let Y represent the number of seashells with lengths greater than 26 mm.

Find P(24.15 < X < 25).

[2]
a.

Find σ , the standard deviation of X.

[3]
b.i.

Hence, find the probability that a seashell selected at random has a length greater than 26 mm.

[2]
b.ii.

Find E(Y).

[3]
c.

Find the probability that exactly three of these seashells have a length greater than 26 mm.

[2]
d.

A seashell selected at random has a length less than 26 mm.

Find the probability that its length is between 24.15 mm and 25 mm.

[3]
e.



Events A and B are independent and P(A)=3P(B).

Given that P(AB)=0.68, find P(B).




The following table below shows the marks scored by seven students on two different mathematics tests.

Let L1 be the regression line of x on y. The equation of the line L1 can be written in the form x = ay + b.

Find the value of a and the value of b.

[2]
a.

Let L2 be the regression line of y on x. The lines L1 and L2 pass through the same point with coordinates (p , q).

Find the value of p and the value of q.

[3]
b.



Contestants in a TV gameshow try to get through three walls by passing through doors without falling into a trap. Contestants choose doors at random.
If they avoid a trap they progress to the next wall.
If a contestant falls into a trap they exit the game before the next contestant plays.
Contestants are not allowed to watch each other attempt the game.

The first wall has four doors with a trap behind one door.

Ayako is a contestant.

Natsuko is the second contestant.

The second wall has five doors with a trap behind two of the doors.

The third wall has six doors with a trap behind three of the doors.

The following diagram shows the branches of a probability tree diagram for a contestant in the game.

Write down the probability that Ayako avoids the trap in this wall.

[1]
a.

Find the probability that only one of Ayako and Natsuko falls into a trap while attempting to pass through a door in the first wall.

[3]
b.

Copy the probability tree diagram and write down the relevant probabilities along the branches.

[3]
c.

A contestant is chosen at random. Find the probability that this contestant fell into a trap while attempting to pass through a door in the second wall.

[2]
d.i.

A contestant is chosen at random. Find the probability that this contestant fell into a trap.

[3]
d.ii.

120 contestants attempted this game.

Find the expected number of contestants who fell into a trap while attempting to pass through a door in the third wall.

[3]
e.



The principal of a high school is concerned about the effect social media use might be having on the self-esteem of her students. She decides to survey a random sample of 9 students to gather some data. She wants the number of students in each grade in the sample to be, as far as possible, in the same proportion as the number of students in each grade in the school.

The number of students in each grade in the school is shown in table.

In order to select the 3 students from grade 12, the principal lists their names in alphabetical order and selects the 28th, 56th and 84th student on the list.

Once the principal has obtained the names of the 9 students in the random sample, she surveys each student to find out how long they used social media the previous day and measures their self-esteem using the Rosenberg scale. The Rosenberg scale is a number between 10 and 40, where a high number represents high self-esteem.

State the name for this type of sampling technique.

[1]
a.

Show that 3 students will be selected from grade 12.

[3]
b.i.

Calculate the number of students in each grade in the sample.

[2]
b.ii.

State the name for this type of sampling technique.

[1]
c.

Calculate Pearson’s product moment correlation coefficient, r .

[2]
d.i.

Interpret the meaning of the value of r  in the context of the principal’s concerns.

[1]
d.ii.

Explain why the value of r  makes it appropriate to find the equation of a regression line.

[1]
d.iii.

Another student at the school, Jasmine, has a self-esteem value of 29.            

By finding the equation of an appropriate regression line, estimate the time Jasmine spent on social media the previous day.

[4]
e.



A healthy human body temperature is 37.0 °C. Eight people were medically examined and the difference in their body temperature (°C), from 37.0 °C, was recorded. Their heartbeat (beats per minute) was also recorded.

Draw a scatter diagram for temperature difference from 37 °C ( x ) against heartbeat ( y ). Use a scale of 2 cm for 0.1 °C on the horizontal axis, starting with −0.3 °C. Use a scale of 1 cm for 2 heartbeats per minute on the vertical axis, starting with 60 beats per minute.

[4]
a.

Write down, for this set of data the mean temperature difference from 37 °C, x ¯ .

[1]
b.i.

Write down, for this set of data the mean number of heartbeats per minute, y ¯ .

[1]
b.ii.

Plot and label the point M( x ¯ , y ¯ ) on the scatter diagram.

[2]
c.

Use your graphic display calculator to find the Pearson’s product–moment correlation coefficient, r .

[2]
d.i.

Hence describe the correlation between temperature difference from 37 °C and heartbeat.

[2]
d.ii.

Use your graphic display calculator to find the equation of the regression line y on x .

[2]
e.

Draw the regression line y on x on the scatter diagram.

[2]
f.



A group of 66 people went on holiday to Hawaii. During their stay, three trips were arranged: a boat trip ( B ), a coach trip ( C ) and a helicopter trip ( H ).

From this group of people:

went on all three trips;
16  went on the coach trip only;
13  went on the boat trip only;
went on the helicopter trip only;
went on the coach trip and the helicopter trip but not the boat trip;
2 went on the boat trip and the helicopter trip but not the coach trip;
4 went on the boat trip and the coach trip but not the helicopter trip;
did not go on any of the trips.

One person in the group is selected at random.

Draw a Venn diagram to represent the given information, using sets labelled B , C and H .

[5]
a.

Show that x = 3 .

[2]
b.

Write down the value of n ( B C ) .

[1]
c.

Find the probability that this person

(i)     went on at most one trip;

(ii)     went on the coach trip, given that this person also went on both the helicopter trip and the boat trip.

[4]
d.



The following table shows the mean weight, y kg , of children who are x years old.

The relationship between the variables is modelled by the regression line with equation  y = a x + b .

Find the value of a and of b.

[3]
a.i.

Write down the correlation coefficient.

[1]
a.ii.

Use your equation to estimate the mean weight of a child that is 1.95 years old.

[2]
b.



Ten students were surveyed about the number of hours, x , they spent browsing the Internet during week 1 of the school year. The results of the survey are given below.

i = 1 10 x i = 252 ,   σ = 5  and median = 27.

Find the mean number of hours spent browsing the Internet.

[2]
a.

During week 2, the students worked on a major project and they each spent an additional five hours browsing the Internet. For week 2, write down

(i)     the mean;

(ii)     the standard deviation.

[2]
b.

During week 3 each student spent 5% less time browsing the Internet than during week 1. For week 3, find

(i)     the median;

(ii)     the variance.

[6]
c.



The following table shows the systolic blood pressures, p mmHg, and the ages, t years, of 6 male patients at a medical clinic.

The relationship between t and p can be modelled by the regression line of p on t with equation p=at+b .

A 50‐year‐old male patient enters the medical clinic for his appointment.

Determine the value of Pearson’s product‐moment correlation coefficient, r, for these data.

[2]
a.i.

Interpret, in context, the value of r found in part (a) (i).

[1]
a.ii.

Find the equation of the regression line of p on t.

[2]
b.

Use the regression equation from part (b) to predict this patient’s systolic blood pressure.

[2]
c.

A 16‐year‐old male patient enters the medical clinic for his appointment.

Explain why the regression equation from part (b) should not be used to predict this patient’s systolic blood pressure.

[1]
d.



A nationwide study on reaction time is conducted on participants in two age groups. The participants in Group X are less than 40 years old. Their reaction times are normally distributed with mean 0.489 seconds and standard deviation 0.07 seconds.

The participants in Group Y are 40 years or older. Their reaction times are normally distributed with mean 0.592 seconds and standard deviation σ seconds.

In the study, 38 % of the participants are in Group X.

A person is selected at random from Group X. Find the probability that their reaction time is greater than 0.65 seconds.

[2]
a.

The probability that the reaction time of a person in Group Y is greater than 0.65 seconds is 0.396. Find the value of σ.

[4]
b.

A randomly selected participant has a reaction time greater than 0.65 seconds. Find the probability that the participant is in Group X.

[6]
c.

Ten of the participants with reaction times greater than 0.65 are selected at random. Find the probability that at least two of them are in Group X.

[3]
d.



SpeedWay airline flies from city A to city B . The flight time is normally distributed with a mean of 260 minutes and a standard deviation of 15 minutes.

A flight is considered late if it takes longer than 275 minutes.

The flight is considered to be on time if it takes between m and 275 minutes. The probability that a flight is on time is 0.830 .

During a week, SpeedWay has 12 flights from city A to city B . The time taken for any flight is independent of the time taken by any other flight.

Calculate the probability a flight is not late.

[2]
a.

Find the value of m .

[3]
b.

Calculate the probability that at least 7 of these flights are on time.

[3]
c.i.

Given that at least 7 of these flights are on time, find the probability that exactly 10 flights are on time.

[4]
c.ii.

SpeedWay increases the number of flights from city A to city B to 20 flights each week, and improves their efficiency so that more flights are on time. The probability that at least 19 flights are on time is 0.788 .

A flight is chosen at random. Calculate the probability that it is on time.

[3]
d.



The mass M of apples in grams is normally distributed with mean μ. The following table shows probabilities for values of M.

The apples are packed in bags of ten.

Any apples with a mass less than 95 g are classified as small.

Write down the value of k.

[2]
a.i.

Show that μ = 106.

[2]
a.ii.

Find P(M < 95) .

[5]
b.

Find the probability that a bag of apples selected at random contains at most one small apple.

[3]
c.

Find the expected number of bags in this crate that contain at most one small apple.

[3]
d.i.

Find the probability that at least 48 bags in this crate contain at most one small apple.

[2]
d.ii.



Two events A and B are such that P(A) = 0.62 and P ( A B ) = 0.18.

Find P(AB′ ).

[2]
a.

Given that P((AB)′) = 0.19, find P(A |B).

[4]
b.



A bakery makes two types of muffins: chocolate muffins and banana muffins.

The weights, C grams, of the chocolate muffins are normally distributed with a mean of 62g and standard deviation of 2.9g.

The weights, B grams, of the banana muffins are normally distributed with a mean of 68g and standard deviation of 3.4g.

Each day 60% of the muffins made are chocolate.

On a particular day, a muffin is randomly selected from all those made at the bakery.

The machine that makes the chocolate muffins is adjusted so that the mean weight of the chocolate muffins remains the same but their standard deviation changes to σg. The machine that makes the banana muffins is not adjusted. The probability that the weight of a randomly selected muffin from these machines is less than 61g is now 0.157.

Find the probability that a randomly selected chocolate muffin weighs less than 61g.

[2]
a.

In a random selection of 12 chocolate muffins, find the probability that exactly 5 weigh less than 61g.

[2]
b.

Find the probability that the randomly selected muffin weighs less than 61g.

[4]
c.i.

Given that a randomly selected muffin weighs less than 61g, find the probability that it is chocolate.

[3]
c.ii.

Find the value of σ.

[5]
d.



The number of messages, M , that six randomly selected teenagers sent during the month of October is shown in the following table. The table also shows the time, T , that they spent talking on their phone during the same month.

The relationship between the variables can be modelled by the regression equation M = a T + b .

Write down the value of a and of b .

[3]
a.

Use your regression equation to predict the number of messages sent by a teenager that spent 154 minutes talking on their phone in October.

[3]
b.



A random sample of nine adults were selected to see whether sleeping well affected their reaction times to a visual stimulus. Each adult’s reaction time was measured twice.

The first measurement for reaction time was taken on a morning after the adult had slept well. The second measurement was taken on a morning after the same adult had not slept well.

The box and whisker diagrams for the reaction times, measured in seconds, are shown below.

Consider the box and whisker diagram representing the reaction times after sleeping well.

State the median reaction time after sleeping well.

[1]
a.

Verify that the measurement of 0.46 seconds is not an outlier.

[3]
b.

State why it appears that the mean reaction time is greater than the median reaction time.

[1]
c.

Now consider the two box and whisker diagrams.

Comment on whether these box and whisker diagrams provide any evidence that might suggest that not sleeping well causes an increase in reaction time.

[1]
d.



A six-sided biased die is weighted in such a way that the probability of obtaining a “six” is 7 10 .

The die is tossed five times. Find the probability of obtaining at most three “sixes”.

[3]
a.

The die is tossed five times. Find the probability of obtaining the third “six” on the fifth toss.

[3]
b.



A group of 800 students answered 40 questions on a category of their choice out of History, Science and Literature.

For each student the category and the number of correct answers, N , was recorded. The results obtained are represented in the following table.

N17/5/MATSD/SP2/ENG/TZ0/01

A χ 2 test at the 5% significance level is carried out on the results. The critical value for this test is 12.592.

State whether N is a discrete or a continuous variable.

[1]
a.

Write down, for N , the modal class;

[1]
b.i.

Write down, for N , the mid-interval value of the modal class.

[1]
b.ii.

Use your graphic display calculator to estimate the mean of N ;

[2]
c.i.

Use your graphic display calculator to estimate the standard deviation of N .

[1]
c.ii.

Find the expected frequency of students choosing the Science category and obtaining 31 to 40 correct answers.

[2]
d.

Write down the null hypothesis for this test;

[1]
e.i.

Write down the number of degrees of freedom.

[1]
e.ii.

Write down the p -value for the test;

[1]
f.i.

Write down the χ 2 statistic.

[2]
f.ii.

State the result of the test. Give a reason for your answer.

[2]
g.



A random variable X is normally distributed with mean, μ . In the following diagram, the shaded region between 9 and μ represents 30% of the distribution.

M17/5/MATME/SP2/ENG/TZ1/09

The standard deviation of X is 2.1.

The random variable Y is normally distributed with mean λ and standard deviation 3.5. The events X > 9 and Y > 9 are independent, and P ( ( X > 9 ) ( Y > 9 ) ) = 0.4 .

Find P ( X < 9 ) .

[2]
a.

Find the value of μ .

[3]
b.

Find λ .

[5]
c.

Given that Y > 9 , find P ( Y < 13 ) .

[5]
d.



A jigsaw puzzle consists of many differently shaped pieces that fit together to form a picture.

Jill is doing a 1000-piece jigsaw puzzle. She started by sorting the edge pieces from the interior pieces. Six times she stopped and counted how many of each type she had found. The following table indicates this information.

Jill models the relationship between these variables using the regression equation y = a x + b .

Write down the value of a and of b .

[3]
a.

Use the model to predict how many edge pieces she had found when she had sorted a total of 750 pieces.

[3]
b.



Ten students were asked for the distance, in km, from their home to school. Their responses are recorded below.

0.3         0.4         3         3         3.5         5         7         8         8         10

The following box-and-whisker plot represents this data.

For these data, find the mean distance from a student’s home to school.

[2]
a.

Find the value of p .

[1]
b.

Find the interquartile range.

[2]
c.



A jar contains 5 red discs, 10 blue discs and m green discs. A disc is selected at random and replaced. This process is performed four times.

Write down the probability that the first disc selected is red.

[1]
a.

Let X be the number of red discs selected. Find the smallest value of m for which Var ( X   ) < 0.6 .

[5]
b.



In Lucy’s music academy, eight students took their piano diploma examination and achieved scores out of 150. For her records, Lucy decided to record the average number of hours per week each student reported practising in the weeks prior to their examination. These results are summarized in the table below.

Find Pearson’s product-moment correlation coefficient, r, for these data.

[2]
a.

The relationship between the variables can be modelled by the regression equation D=ah+b. Write down the value of a and the value of b.

[1]
b.

One of these eight students was disappointed with her result and wished she had practised more. Based on the given data, determine how her score could have been expected to alter had she practised an extra five hours per week.

[2]
c.



A discrete random variable X has the following probability distribution.

N17/5/MATME/SP2/ENG/TZ0/04

Find the value of k .

[4]
a.

Write down P ( X = 2 ) .

[1]
b.

Find P ( X = 2 | X > 0 ) .

[3]
c.



The maximum temperature T , in degrees Celsius, in a park on six randomly selected days is shown in the following table. The table also shows the number of visitors, N , to the park on each of those six days.

M17/5/MATME/SP2/ENG/TZ2/02

The relationship between the variables can be modelled by the regression equation N = a T + b .

Find the value of a and of b .

[3]
a.i.

Write down the value of  r .

[1]
a.ii.

Use the regression equation to estimate the number of visitors on a day when the maximum temperature is 15 °C.

[3]
b.



A data set consisting of 16 test scores has mean 14.5 . One test score of 9 requires a second marking and is removed from the data set.

Find the mean of the remaining 15 test scores.




In a large university the probability that a student is left handed is 0.08. A sample of 150 students is randomly selected from the university. Let k be the expected number of left-handed students in this sample.

Find k .

[2]
a.

Hence, find the probability that exactly k students are left handed;

[2]
b.i.

Hence, find the probability that fewer than k students are left handed.

[2]
b.ii.



A discrete random variable, X, has the following probability distribution:

Show that 2k2-k+0.12=0.

[1]
a.

Find the value of k, giving a reason for your answer.

[3]
b.

Hence, find E(X).

[2]
c.



A discrete random variable X has the following probability distribution.

Find an expression for q in terms of p.

[2]
a.

Find the value of p which gives the largest value of EX.

[3]
b.i.

Hence, find the largest value of EX.

[1]
b.ii.



Consider the function  f ( x ) = x 2 e 3 x ,   x R .

The graph of f has a horizontal tangent line at x = 0 and at x = a . Find a .