QCEVault

Statistical inference — Question 243

Original QCE Vault practice · 6 marks

Q243 · Practice questionTechnology-activeComplex unfamiliar6 marks

QUESTION 243 (6 marks)

A lot of miniature game pieces is accepted when its random sample mean mass is at least 49 g. Independent masses are normal with known standard deviation 6 g. A good lot has mean 50 g and a poor lot mean 48 g.
a)
For n=36, find the probabilities of rejecting a good lot and rejecting a poor lot.
[3 marks]
b)
Find least n making good-lot rejection probability at most 0.05. Do not round the quantile before deciding n.
[3 marks]
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