AQA GCSE Statistics — Paper 1 (Higher)
Total marks: 82 · Duration: 1 hour 50 minutes · Tier: higher
Instructions to candidates
• Answer all questions. • Use black ink or black ball-point pen. You may use an HB pencil for graphs. • You must show all your working; marks may be given for a correct method even if the answer is wrong. • A scientific calculator is required. • Give your answers to an appropriate degree of accuracy where a rounded answer is needed. • The total number of marks for this paper is 82. • All data you need is given within the questions in tables; no separate insert is required, and any graph or chart referred to is one you are asked to describe or construct yourself.
Paper
1. A student records the number of text messages received by each of 20 people in one hour. The results are:
| Messages | 0 | 1 | 2 | 3 | 4 | 5 |
|---|---|---|---|---|---|---|
| Frequency | 3 | 5 | 4 | 4 | 2 | 2 |
(a) Write down the modal number of messages. (1 mark) (b) Find the median number of messages. (2 marks) (c) Calculate the mean number of messages. (3 marks)
2. The table shows the times, t minutes, taken by 60 students to travel to school.
| Time (t min) | 0 < t ≤ 10 | 10 < t ≤ 20 | 20 < t ≤ 30 | 30 < t ≤ 40 | 40 < t ≤ 50 |
|---|---|---|---|---|---|
| Frequency | 12 | 20 | 15 | 9 | 4 |
(a) Write down the modal class. (1 mark) (b) Calculate an estimate of the mean travel time. (4 marks) (c) Explain why your answer to part (b) is only an estimate. (1 mark)
3. The mean of five numbers is 14. When a sixth number is included, the mean becomes 15. Find the sixth number. (3 marks)
4. A company classifies its 240 employees by department. It wants to take a stratified sample of 40 employees.
| Department | Sales | Production | Admin | Delivery |
|---|---|---|---|---|
| Employees | 96 | 84 | 36 | 24 |
(a) Explain what is meant by a stratified sample. (1 mark) (b) Calculate the number of employees that should be sampled from the Production department. (2 marks) (c) Give one advantage of a stratified sample over a simple random sample here. (1 mark)
5. The cumulative frequency table shows the masses, m grams, of 80 apples.
| Mass (m ≤) | 100 | 120 | 140 | 160 | 180 |
|---|---|---|---|---|---|
| Cumulative frequency | 6 | 26 | 58 | 74 | 80 |
(a) Use the table to estimate the median mass. (2 marks) (b) Estimate the interquartile range. (3 marks) (c) An apple is classed as "large" if its mass is more than 165 g. Estimate the number of large apples. (2 marks)
6. The table shows the number of hours of sunshine, x, and the number of ice creams sold, y, on eight days.
| x (hours) | 2 | 3 | 5 | 6 | 7 | 8 | 9 | 10 |
|---|---|---|---|---|---|---|---|---|
| y (sold) | 14 | 20 | 30 | 34 | 42 | 48 | 52 | 60 |
(a) Describe the correlation between x and y. (1 mark) (b) The equation of the line of best fit is y = 5.6x + 3. Use it to estimate the number of ice creams sold when there are 4 hours of sunshine. (2 marks) (c) Explain why it would not be sensible to use this equation to estimate sales for 20 hours of sunshine. (1 mark) (d) Interpret the value 5.6 in the equation of the line of best fit. (1 mark)
7. A spinner has four sections coloured red, blue, green and yellow. The probability of each colour is shown, with the probability of yellow unknown.
| Colour | Red | Blue | Green | Yellow |
|---|---|---|---|---|
| Probability | 0.3 | 0.25 | 0.2 | y |
(a) Find the value of y. (2 marks) (b) The spinner is spun 200 times. Estimate the number of times it lands on blue. (2 marks) (c) The spinner is spun twice. Find the probability that it lands on red both times. (2 marks)
8. The table shows the amount spent, £s, by customers in a shop.
| Spend (£s) | 0 < s ≤ 20 | 20 < s ≤ 40 | 40 < s ≤ 80 |
|---|---|---|---|
| Frequency | 30 | 24 | 16 |
A histogram is to be drawn for this data.
(a) Explain why frequency density, rather than frequency, must be plotted on the vertical axis. (1 mark) (b) Calculate the frequency density for each of the three classes. (3 marks) (c) On a histogram, the bar for the class 0 < s ≤ 20 has a height of 1.5 units. State the height that the bar for 40 < s ≤ 80 should have on the same scale. (2 marks)
9. A quality inspector records the number of faulty items in samples of 50 taken from a production line each day for 10 days:
2, 3, 1, 4, 2, 6, 3, 2, 5, 2
(a) Find the range of the number of faulty items. (1 mark) (b) Find the median and the interquartile range. (4 marks) (c) On day 11 a sample contains 12 faulty items. Using an appropriate calculation, explain whether 12 should be regarded as an outlier. (3 marks)
10. The table shows the population of a town, in thousands, over five years, and the index numbers for the cost of living (2020 = 100).
| Year | 2020 | 2021 | 2022 | 2023 | 2024 |
|---|---|---|---|---|---|
| Population (000s) | 40 | 42 | 45 | 47 | 50 |
| Cost-of-living index | 100 | 104 | 111 | 118 | 126 |
(a) Calculate the percentage increase in population from 2020 to 2024. (2 marks) (b) Interpret the cost-of-living index value of 126 in 2024. (1 mark) (c) A worker earned £24 000 in 2020. To keep pace with the cost of living, what would their salary need to be in 2024? (2 marks)
11. A statistician investigates whether a six-sided die is fair by rolling it 120 times. The observed frequencies are:
| Score | 1 | 2 | 3 | 4 | 5 | 6 |
|---|---|---|---|---|---|---|
| Frequency | 15 | 22 | 18 | 25 | 20 | 20 |
(a) State how many times each score would be expected if the die were fair. (1 mark) (b) Give one reason why the observed frequencies differing from the expected value does not, by itself, prove the die is biased. (1 mark) (c) Calculate the mean score obtained across the 120 rolls. (3 marks)
12. In a town, 60% of households own a car. Of those that own a car, 40% also own a bicycle. Of those that do not own a car, 75% own a bicycle.
(a) Complete a tree diagram for this information by stating the four probabilities on the second branches (car → bicycle, car → no bicycle, no car → bicycle, no car → no bicycle). (2 marks) (b) Find the probability that a household chosen at random owns a bicycle. (3 marks) (c) Find the probability that a household owns a car, given that it owns a bicycle. (3 marks)
13. The daily maximum temperatures, in °C, recorded in a town over seven days were:
18, 21, 19, 24, 20, 22, 17
(a) Calculate the mean temperature. (2 marks) (b) Calculate the standard deviation of the temperatures, giving your answer to 2 decimal places. (4 marks) (c) A second town over the same week had a mean of 20 °C and a standard deviation of 4.8 °C. Compare the temperatures of the two towns. (2 marks)
14. The quarterly sales, in £000s, of a small business are shown.
| Q1 | Q2 | Q3 | Q4 | |
|---|---|---|---|---|
| Year 1 | 12 | 18 | 24 | 14 |
| Year 2 | 16 | 22 | 28 | 18 |
(a) Explain why a four-point moving average is appropriate for this data. (1 mark) (b) Calculate the first two four-point moving averages. (3 marks) (c) State what the trend in the moving averages suggests about the business. (1 mark)