Mathematics 9709 · AS & A Level · Sampling and estimation
Sampling and estimation — practice question
A javelin thrower recorded the distances of a random sample of $50$ of her attempts. The sample mean was $72.3\,\text{m}$ and an unbiased estimate of the population variance was $64.3\,\text{m}^2$.
(a)[3]
Find a $92\%$ confidence interval for the population mean length of throws for this athlete.
(b)[1]
A discus thrower wants to work out a $92\%$ confidence interval for the population mean length of his throws. He bases the calculation on his first $50$ throws in a week. Comment on this method.
Worked solution & mark scheme
This 4-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Correct confidence interval form $72.3 \pm z\sqrt{\frac{64.3}{50}}$ with $z$ given” …