(a)[3]
Calculate unbiased estimates for the population mean and the variance of $X$.
(b)[1]
State one necessary condition for the estimates from part (a) to be reliable.
Mathematics 9709 · AS & A Level · Sampling and estimation
Sampling and estimation — practice question
The lengths, $X\text{ cm}$, for a sample of 100 insects of one particular type were summarised like this:
$n = 100$, $\sum x = 36.8$, $\sum x^2 = 17.34$.
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This 4-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Estimate for the mean, $\text{est}(\mu)=0.368=\frac{46}{125}$” …
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