confidence interval

A clinical trial was conducted to test the effectiveness of a drug for treating insomnia in older subjects Before treatment, 17 subjects had a mean wake time of 100.0 min. After treatment, the 17 subjects had a mean wake time of 91.6 min and a standard deviation of 23.7 min. Assume that the 17 sample values appear to be from a normally distributed population and construct a 99% confidence interval estimate of the mean wake time for a population with drug treatments. What does the result suggest about the mean wake time of 100.0 min before the treatment? Does the drug appear to be effective? Construct the 99% confidence interval estimate of the mean wake time for a population with the treatment. min