(a)[6]
Calculate a $98\%$ confidence interval for the population mean time.
(b)[1]
Explain why the Central Limit Theorem had to be used in part (a).
Mathematics 9709 · AS & A Level · Sampling and estimation
Sampling and estimation — practice question
A construction company records, in $t$ days, how long it takes to construct each house of one particular design. For a random sample of $60$ such houses, the summary data are given by: $\sum t = 4820$, $\sum t^2 = 392050$.
Worked solution & mark scheme
This 7-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Obtain $\mu = \frac{4820}{60} = \frac{241}{3} = 80.3$ (3 s.f.)” …
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