QCEVault

Statistical inference — Question 98

Original QCE Vault practice · 5 marks

Q98 · Practice questionComplex familiar5 marks

QUESTION 98 (5 marks)

A population has mean 18 and standard deviation 4.5. Random samples of size 81 are taken.
a)
State the approximate distribution of Xˉ\bar X.
[2 marks]
b)
Determine P(17.2<Xˉ<18.6)P(17.2<\bar X<18.6) to four decimal places.
[3 marks]
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