QCEVault

Statistical inference — Question 140

Original QCE Vault practice · 5 marks

Q140 · Practice questionTechnology-activeComplex familiar5 marks

QUESTION 140 (5 marks)

Two groups of sizes 4040 and 6060 have sample means 8484 and 7878 respectively. Treat the combined data as one sample with standard deviation 1010 and use z=1.96z=1.96.
a)
Find the combined sample mean.
[2 marks]
b)
Estimate the standard error of the combined mean.
[1 mark]
c)
Construct the approximate 95%95\% confidence interval.
[2 marks]
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