Question

Exposure to Lead

A simple random sample of 22 full IQ scores for the group with medium exposure to lead was taken. The sample standard deviation of this sample is 14.3. Construct a 95% confidence interval estimate for the population standard deviation.

Requirements:

a) Simple random sample

b) Check normality

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Answer #1

given data are:-

sample size (n ) = 22

sample sd (s) = 14.3

the chi square critical value table be:-

critical value excel function
=CHISQ.INV.RT(0.025,21)
=CHISQ.INV.RT(0.975,21)

the 95% confidence interval for the population standard deviation be:-

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