1. A clinical trial was conducted to test the effectiveness of a drug for treating insomnia in older subjects. Before treatment,

13 subjects had a mean wake time of 100.0 min. After treatment, the 13 subjects had a mean wake time of 79.1 min and a standard deviation of 21.8 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 100.0 min before the treatment? Does the drug appear to be effective?

-Construct the 90% confidence interval estimate of the mean wake time for a population with the treatment.

2.Listed below are student evaluation ratings of courses, where a rating of 5 is for "excellent." The ratings were obtained at one university in a state. Construct a confidence interval using a 90% confidence level. What does the confidence interval tell about the population of all college students in the state?

4.0, 3.2, 3.9, 4.8, 2.8, 4.0, 3.3, 4.6,4.7, 4.2, 4.2, 3.6, 3.1, 3.8, 4.1

-What is the confidence interval for the population mean ?