QCEVault

Statistical inference — Question 124

Original QCE Vault practice · 6 marks

Q124 · Practice questionTechnology-freeComplex familiar6 marks

QUESTION 124 (6 marks)

A 99%99\% confidence interval for a mean is centred at 4040 and has total width 5.1525.152. It uses z=2.576z=2.576 and sample standard deviation s=10s=10.
a)
Estimate the sample size used.
[3 marks]
b)
Does the interval support the claim that μ=38\mu =38? Explain.
[2 marks]
c)
State the approximate newnew width if the sample size is quadrupled.
[1 mark]
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