A clinical trial was conducted to test the effectiveness of a drug used for treating insomnia in older subjects. After treatment with the drug,

13

subjects had a mean wake time of

90.1

min and a standard deviation of

41.5

min. Assume that the

13

sample values appear to be from a normally distributed population and construct a

98%

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?

Question content area bottom

Part 1

Find the confidence interval estimate.