1
A biologist is estimating the number of fish in a lake. She catches, tags and releases 40 fish. A week later she catches 50 fish and finds that 8 of them are tagged.
Either calculator policy
(a)Use this information to estimate the total number of fish in the lake.
(2)
(b)Give one reason why this estimate may not be reliable.
(1)
(Total for Question 1 is 3 marks)
2
The frequency table shows the favourite subject of 90 students. Maths 20, English 25, Science 30, Other 15. A pie chart is to be drawn to show this information.
Either calculator policy
(a)Work out the size of the angle that would represent Science on the pie chart.
(2)
(b)Write the fraction of students who chose Maths in its simplest form.
(1)
(Total for Question 2 is 3 marks)
3
A rugby coach records the number of points his team scored in each of 11 matches: 12, 15, 15, 18, 20, 21, 22, 24, 25, 26, 78.
Either calculator policy
(a)Find the median number of points scored.
(1)
(b)The coach says, "The mean is the best statistic to describe our typical score." The mean of the 11 scores is just over 25. Explain why the coach is wrong.
(1)
(Total for Question 3 is 2 marks)
4
The revision time (in hours) and test mark of 8 students were recorded and plotted on a scatter graph. The points show a clear upward trend. A line of best fit is drawn; it passes through the points (2, 30) and (8, 66).
Either calculator policy
(a)Describe the correlation shown by the scatter graph.
(1)
(b)Use the line of best fit to estimate the test mark of a student who revised for 5 hours.
(2)
(c)Explain why using the line of best fit to estimate the mark for a student who revised 15 hours may not be reliable.
(1)
(Total for Question 4 is 4 marks)
5
Two classes sat the same test, marked out of 100. For Class A the median mark was 62 and the range was 24. For Class B the median mark was 55 and the range was 10.
Either calculator policy
(a)Compare the results of the two classes. Make two clear comparisons, referring to the figures given.
(2)
(b)Give one reason why the range may not be a reliable measure of spread.
(1)
(Total for Question 5 is 3 marks)
6
The table shows how 72 people travel to work: Car 30, Bus 18, Walk 15, Cycle 9.
Either calculator policy
(a)Work out the angle that would represent 'Bus' on a pie chart.
(2)
(b)Write the fraction of the people who cycle to work, giving your answer in its simplest form.
(1)
(Total for Question 6 is 3 marks)
7
A pictogram is used to show the number of emails a company receives each day. A full circle represents 10 emails, and part-circles are used for smaller amounts. On Monday the pictogram shows 3.5 circles. On Tuesday it shows 2 circles.
Either calculator policy
(a)Work out the number of emails received on Monday.
(1)
(b)On Wednesday the company received 45 emails. Work out the number of circles that should be drawn for Wednesday.
(1)
(c)Work out the total number of emails received on Monday, Tuesday and Wednesday together.
(2)
(Total for Question 7 is 4 marks)
8
Here are five numbers: 5, 8, 3, 8, 6
Either calculator policy
(Total for Question 8 is 4 marks)
9
A council wants to find out how often adults in a town exercise. A researcher asks 40 people as they leave a gym.
Either calculator policy
Explain why this sample may not represent all adults in the town. Suggest a better sampling method.
(2)
(Total for Question 9 is 2 marks)
10
A factory makes 1250 components in one day. A quality inspector chooses a random starting component from the first 25 and then inspects every 25th component.
Non-calculator
(a)Work out how many components are inspected.
(2)
(b)State one possible limitation of this systematic sample.
(1)
(Total for Question 10 is 3 marks)
11
A scientist is estimating the number of ladybirds in a greenhouse. She catches, marks and releases 48 ladybirds. Later she catches 60 ladybirds, of which 12 are marked.
Calculator
(a)Estimate the total number of ladybirds in the greenhouse.
(2)
(b)State two assumptions needed for this estimate to be reliable.
(2)
(c)Some marked ladybirds moved out of the greenhouse before the second sample. Explain how this is likely to affect the estimate.
(1)
(Total for Question 11 is 5 marks)
12
The travel methods used by 10 students are: bus, walk, cycle, bus, bus, walk, cycle, bus, walk, bus.
Non-calculator
(a)Complete a frequency list for the three travel methods.
(2)
(b)Write down the total frequency.
(1)
(Total for Question 12 is 3 marks)
13
The numbers of visitors to a museum in six consecutive months were: January 120, February 135, March 150, April 145, May 170, June 185.
Calculator
(a)Describe the trend in the number of visitors.
(2)
(b)Work out the percentage increase from January to June. Give your answer to 1 decimal place.
(2)
(Total for Question 13 is 4 marks)
14
The frequency distribution for the number of books read by 25 students in one month is: 0 books, frequency 4; 1 book, frequency 7; 2 books, frequency 9; 3 books, frequency 5.
Either calculator policy
(a)Show that the total frequency is 25.
(1)
(b)A vertical line chart is drawn for this distribution. Write the four coordinate pairs (number of books, frequency) that are plotted.
(2)
(Total for Question 14 is 3 marks)
15
The times, t minutes, taken by 38 people to complete a puzzle are grouped as follows: 0 < t ≤ 10, frequency 8; 10 < t ≤ 15, frequency 12; 15 < t ≤ 30, frequency 18.
Calculator
(a)Work out the frequency density for each class.
(3)
(b)Which class has the tallest bar in the histogram?
(1)
(Total for Question 15 is 4 marks)
16
A histogram represents the masses, m kg, of 40 parcels. For 0 < m ≤ 5 the frequency density is 2.4. For 5 < m ≤ 15 the frequency density is 1.1. The remaining parcels are in the class 15 < m ≤ 20.
Calculator
(a)Work out the frequency in each of the first two classes.
(2)
(b)Work out the frequency density for the class 15 < m ≤ 20.
(2)
(Total for Question 16 is 4 marks)
17
A cumulative frequency graph represents 80 values. Reading from the graph gives: cumulative frequency 20 at value 18; cumulative frequency 40 at value 27; cumulative frequency 60 at value 39; cumulative frequency 80 at value 52.
Non-calculator
(a)Write down an estimate for the median.
(1)
(b)Work out an estimate for the interquartile range.
(2)
(c)Estimate the number of values greater than 39.
(1)
(Total for Question 17 is 4 marks)
18
The scores in a quiz have this frequency distribution: score 1, frequency 2; score 2, frequency 3; score 3, frequency 4; score 4, frequency 1.
Non-calculator
(a)Work out the mean score.
(2)
(Total for Question 18 is 4 marks)
19
Two groups complete the same task. For Group A the median time is 18 minutes and the interquartile range is 6 minutes. For Group B the median time is 21 minutes and the interquartile range is 11 minutes.
Either calculator policy
Compare the times for the two groups. Make one comparison of typical time and one comparison of spread.
(2)
(Total for Question 19 is 2 marks)
20
Six numbers have a mean of 14. Five of the numbers are 9, 11, 13, 17 and 18.
Calculator
(a)Work out the sixth number.
(3)
(b)A seventh number, 40, is added. Work out the new mean. Give your answer to 1 decimal place.
(2)
(Total for Question 20 is 5 marks)
21
In a random sample of 50 households, 12 households do not own a car. The town has 2000 households.
Calculator
Estimate the number of households in the town that do not own a car.
(2)
(Total for Question 21 is 2 marks)
22
The amounts, in pounds, spent by 10 customers are 22, 24, 25, 26, 27, 28, 29, 30, 31 and 180.
Calculator
(c)Which average better describes a typical amount spent? Give a reason.
(1)
(Total for Question 22 is 4 marks)
23
A random sample of 300 adults is taken from across a town. Of these adults, 180 say they prefer travelling by bus rather than by car. There are 4500 adults in the town.
Calculator
(a)Use the sample to estimate how many adults in the town prefer travelling by bus.
(2)
(b)Explain why 2700 should be described as an estimate rather than the exact number.
(2)
(Total for Question 23 is 4 marks)
24
For a group of homes, the data show that as the outdoor temperature increases, the amount spent on heating generally decreases.
Either calculator policy
(a)State the type of correlation.
(1)
(b)Does this statement mean that every warmer day has a lower heating cost than every colder day? Explain your answer.
(1)
(Total for Question 24 is 2 marks)
25
A scatter graph compares hours of practice, x, with a performance score, y. A line of best fit passes through (4, 18) and (10, 42). The observed practice times range from 2 to 11 hours.
Either calculator policy
(a)Use the line of best fit to estimate the score when x = 7.
(2)
(b)Explain why the line of best fit does not prove that extra practice causes a higher score.
(2)
(Total for Question 25 is 4 marks)
26
A scatter graph contains the points (1, 12), (2, 16), (3, 19), (4, 25), (5, 27), (6, 32) and (7, 70). A line of best fit for the first six points passes through (1, 12) and (6, 32).
Calculator
(b)Use the line of best fit to estimate y when x = 4.5.
(2)
(c)State how including the outlier is likely to affect a line of best fit.
(1)
(d)Explain why using the line to predict y when x = 10 may be unreliable.
(1)
(Total for Question 26 is 5 marks)