statistics and probability.........................................................................

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 103 . 0 min . After treatment , the 21 subjects had a mean wake time of 94 . 4 min and a standard deviation of 24 . 6 min . Assume that the 21 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 103 . 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