Question

A clinical trial was conducted to test the effectiveness of a drug used for treating insomnia in older subjects. After treatment with the​ drug, 24 subjects had a mean wake time of 90.8 min and a standard deviation of 43.4 min. Assume that the 24 sample values appear to be from a normally distributed population and construct a 95 ​% confidence interval estimate of the standard deviation of the wake times for a population with the drug treatments. Does the result indicate whether the treatment is​ effective?  

Answer 1

Refer chi-square table or use excel formula "=CHISQ.INV.RT(0.975,23)" & "=CHISQ.INV.RT(0.025,23)" to find the critical values.

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