Mathematics 9709 · AS & A Level · Sampling and estimation

Sampling and estimation — practice question

In a particular diploma, candidates sit two tests. Their first-test and second-test marks are represented by independent variables with distributions $N(38.1, 3.8^2)$ and $N(64.0, 6.1^2)$ respectively. The final mark, $F$, for each candidate is obtained by doubling the first-test mark and then adding that to the second-test mark.
(main)[5]

Determine the probability that the mean, $\bar{F}$, of the final marks for a random sample of $25$ candidates exceeds $143$.

Worked solution & mark scheme

This 5-mark question has a full step-by-step worked solution and mark scheme. One marking point: Correct mean $E(F)=140.2$

  • Full mark scheme, point by point
  • Step-by-step worked solution
  • Write your answer & get it marked instantly by AI