Grade Ladder: Probability and Statistics
18 questions climbing from grade 1 to grade 9 across the probability and statistics content of the Edexcel GCSE, two at each grade. Each question shows its grade, its specification code and whether it is non-calculator.
How to use this ladderFoundation students: work through Grades 1–5. Higher students: start at Grade 4 and push on to 9. Questions marked Non-calculator should be done without a calculator, as in Paper 1.
Grades 1–3 · Foundation
- (1 mark)Grade 1P3Non-calculatorA fair coin is flipped. What is the probability of a head?
- (1 mark)Grade 1S4Non-calculatorFind the mode of 3, 5, 5, 7, 9.
- (2 marks)Grade 2P3Non-calculatorA fair dice is rolled. Find (a) P(even) (b) P(greater than 4).
- (1 mark)Grade 2S4Non-calculatorFind the mean of 4, 7, 9, 12.
- (2 marks)Grade 3S4Non-calculatorFind the median and the range of 12, 5, 9, 15, 7, 10.
- (1 mark)Grade 3P4Non-calculatorP(red) = 0.35. Find P(not red).
Grades 4–5 · Foundation and Higher
- (2 marks)Grade 4P3Non-calculatorThe probability of winning a game is 0.15. Anna plays 300 times. How many times should she expect to win?
- (2 marks)Grade 4S2Non-calculatorIn a survey of 60 people, 15 chose tea. What angle should tea have in a pie chart?
- (2 marks)Grade 5P8Non-calculatorTwo fair coins are flipped. Find the probability of two heads.
- (3 marks)Grade 5S4Estimate the mean.
Time t (s) 0 < t ≤ 10 10 < t ≤ 20 20 < t ≤ 30 Frequency 4 10 6
Grades 6–7 · Higher
- (3 marks)Grade 6P8Non-calculatorA bag has 3 red and 5 blue counters. A counter is taken, replaced, and a second is taken. Find P(both red).
- (2 marks)Grade 6S6Non-calculatorA scatter graph shows that as temperature rises, ice-cream sales rise. Describe the correlation, and explain why it doesn’t prove that heat causes sales.
- (3 marks)Grade 7P8Non-calculatorA bag has 3 red and 5 blue counters. Two are taken without replacement. Find P(both the same colour).
- (2 marks)Grade 7S3Non-calculatorOn a histogram, the class 10 < t ≤ 20 has frequency density 2.4. Find its frequency.
Grades 8–9 · Higher
- (3 marks)Grade 8P9Non-calculatorIn a Venn diagram, A only = 12, A ∩ B = 8, B only = 10 and neither = 10. Find P(A | B).
- (2 marks)Grade 8S3Non-calculatorOn a histogram, the class 15 < t ≤ 30 has frequency density 1.6. Find its frequency.
- (3 marks)Grade 9P8Non-calculatorA fair dice is rolled three times. Find the probability of getting at least one six.
- (4 marks)Grade 9P8Non-calculatorA bag has n counters, 4 of which are red. Two are taken without replacement. P(both red) = 314. Find n.
Worked solutions
Show worked solutions
Grade Ladder: Probability and Statistics — Worked Solutions
Full worked solutions to all 18 questions (39 marks).
Grades 1–3 · Foundation
- (1 mark)Grade 1P3Non-calculatorA fair coin is flipped. What is the probability of a head?Solution
- 2 equally likely outcomes.
12 - (1 mark)Grade 1S4Non-calculatorFind the mode of 3, 5, 5, 7, 9.Solution
- The most common value.
5 - (2 marks)Grade 2P3Non-calculatorA fair dice is rolled. Find (a) P(even) (b) P(greater than 4).Solution
- (a) 2, 4, 6 → 3 out of 6.
- (b) 5, 6 → 2 out of 6.
(a) ½ (b) ⅓ - (1 mark)Grade 2S4Non-calculatorFind the mean of 4, 7, 9, 12.Solution
- 32 ÷ 4.
8 - (2 marks)Grade 3S4Non-calculatorFind the median and the range of 12, 5, 9, 15, 7, 10.Solution
- Order: 5, 7, 9, 10, 12, 15. Median = (9 + 10) ÷ 2.
- Range = 15 − 5.
Median 9.5, range 10 - (1 mark)Grade 3P4Non-calculatorP(red) = 0.35. Find P(not red).Solution
- 1 − 0.35.
0.65
Grades 4–5 · Foundation and Higher
- (2 marks)Grade 4P3Non-calculatorThe probability of winning a game is 0.15. Anna plays 300 times. How many times should she expect to win?Solution
- 0.15 × 300.
45 - (2 marks)Grade 4S2Non-calculatorIn a survey of 60 people, 15 chose tea. What angle should tea have in a pie chart?Solution
- 1560 × 360°.
90° - (2 marks)Grade 5P8Non-calculatorTwo fair coins are flipped. Find the probability of two heads.Solution
- ½ × ½.
14 - (3 marks)Grade 5S4Estimate the mean.
Time t (s) 0 < t ≤ 10 10 < t ≤ 20 20 < t ≤ 30 Frequency 4 10 6 Solution- Midpoints 5, 15, 25.
- Σfx = 20 + 150 + 150 = 320; Σf = 20.
- 320 ÷ 20.
16 s
Grades 6–7 · Higher
- (3 marks)Grade 6P8Non-calculatorA bag has 3 red and 5 blue counters. A counter is taken, replaced, and a second is taken. Find P(both red).Solution
- 38 × 38.
964 - (2 marks)Grade 6S6Non-calculatorA scatter graph shows that as temperature rises, ice-cream sales rise. Describe the correlation, and explain why it doesn’t prove that heat causes sales.Solution
- Positive correlation.
- Correlation shows a relationship, not cause: another factor (such as summer holidays) could affect both.
Positive correlation; correlation ≠ causation - (3 marks)Grade 7P8Non-calculatorA bag has 3 red and 5 blue counters. Two are taken without replacement. Find P(both the same colour).Solution
- P(RR) = 38 × 27 = 656.
- P(BB) = 58 × 47 = 2056.
- Add: 2656.
1328 - (2 marks)Grade 7S3Non-calculatorOn a histogram, the class 10 < t ≤ 20 has frequency density 2.4. Find its frequency.Solution
- Frequency = FD × class width = 2.4 × 10.
24
Grades 8–9 · Higher
- (3 marks)Grade 8P9Non-calculatorIn a Venn diagram, A only = 12, A ∩ B = 8, B only = 10 and neither = 10. Find P(A | B).Solution
- Given B: total 8 + 10 = 18.
- In A as well: 8.
49 - (2 marks)Grade 8S3Non-calculatorOn a histogram, the class 15 < t ≤ 30 has frequency density 1.6. Find its frequency.Solution
- Width 15: 1.6 × 15.
24 - (3 marks)Grade 9P8Non-calculatorA fair dice is rolled three times. Find the probability of getting at least one six.Solution
- P(no six) = (56)³ = 125216.
- 1 − 125216.
91216 - (4 marks)Grade 9P8Non-calculatorA bag has n counters, 4 of which are red. Two are taken without replacement. P(both red) = 314. Find n.Solution
- 4n × 3n − 1 = 314 → 12n(n − 1) = 314 → n(n − 1) = 56.
- n² − n − 56 = 0 → (n − 8)(n + 7) = 0, and n > 0.
n = 8
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