A clinical trial was conducted to test the effectiveness of a drug for treating insomnia in older subjects. Before​ treatment, 21 subjects had a mean wake time of 102 min. After​ treatment, the 21 subjects had a mean wake time of 79.3 min and a standard deviation of 21 min. Assume that the 21 sample values appear to be from a normally distributed population and construct a ​95% 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 102.0 min before the​ treatment? Does the drug appear to be​ effective?