◈ Oracle PrepSign Up Free
A-LevelMathematicsProbability and statistics9709/62 · May/June 2025 · Q23 Marks

The height of a certain species of plant is denoted by Hcm. The heights of a random sample of 100 plants were measured, and the following results were found. • The mean, h, for the sample was 80.2. • An unbiased estimate of the population variance of H was 15.6. Calculate the value of Sh².

Mark scheme

Marking points from the official mark scheme (May/June 2025). The mark or mark type is shown in brackets.

  1. [M1] For attempt biased or unbiased = 15.6.
  2. [A1] For correct expression =15.6.
  3. [A1] Σh² = 644748.4 or 645000 (3 sf) or 3223742/5

Write your answer and get it marked

On Oracle Prep you can write or photograph your own answer and have it marked by AI against this mark scheme, with feedback on what you missed.

Sign up free →

About this question

Topic
Probability and statistics, A-Level Mathematics (syllabus 9709). Structured question, 3 marks.
Source
A-Level Mathematics, May/June 2025 Paper 6 Variant 2, question 2.

Questions and mark schemes are from past examination papers and remain the copyright of the exam board. How Oracle Prep builds its content

Related Mathematics questions

Probability and statisticsFeb/Mar 201713m

The lengths, in centimetres, of middle fingers of women in Raneland have a normal distribution with mean u and standa…

Probability and statisticsFeb/Mar 20184m

A selection of 3 letters from the 8 letters of the word COLLIDER is made.

Probability and statisticsFeb/Mar 20186m

Last Saturday, Sarah recorded the colour and type of 160 cars in a car park. All the cars that were not red or silver…

DifferentiationFeb/Mar 20206m

A curve has equation 3x² - y² – 4 ln(2y + 3) = 26. Find the equation of the tangent to the curve at the point (3, −1).

FunctionsFeb/Mar 20209m

Sketch, on the same diagram, the graphs of y = |x + 2k| and y = |2x – 3k|, where k is a positive constant. Give, in t…

Numerical methodsFeb/Mar 20209m

A curve has equation y = x³e⁻⁰.²ˣ where x ≥ 0. At the point P on the curve, the gradient of the curve is 15.

← Browse all past-paper questions

© 2026 Oracle Prep