A clinical trial was conducted to test the effectiveness of a drug for treating insomnia in older subjects. Before​ treatment, 13subjects had a mean wake time of 100 min. After​ treatment, the 13 subjects had a mean wake time of 95.5 min and a standard deviation of 21.6 min. Assume that the 13 sample values appear to be from a normally distributed population and construct a ​90% 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
min before the​ treatment? Does the drug appear to be​ effective?