QCEVault

Statistical inference — Question 246

Original QCE Vault practice · 5 marks

Q246 · Practice questionTechnology-activeComplex familiar5 marks

QUESTION 246 (5 marks)

A random sample of 64 independent measurements has x‾=14.8,s=1.2\overline x=14.8,s=1.2. The specification limit is 15. Use x‾±1.96s/n\overline x\pm1.96s/\sqrt n.
a)
Does the entire approximate 95 percent interval lie below 15?
[2 marks]
b)
Assuming the same future observed mean and standard deviation, find least n making the upper endpoint strictly below 15.
[3 marks]
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