A clinical trial was conducted to test the effectiveness of adrug used for treating insomnia in older subjects. After treatmentwith the​ drug, 28 subjects had a mean wake time of 96.9 min and astandard deviation of 42.3 min. Assume that the 28 sample valuesappear to be from a normally distributed population and construct a98​% confidence interval estimate of the standard deviation of thewake times for a population with the drug treatments. Does theresult indicate whether the treatment is​ effective? Find theconfidence interval estimate. nothing minless thansigmaless thannothing min ​(Round to two decimal places as​ needed.)
