Question

A clinical trial was conducted to test the effectiveness of a drug for treating insomnia in older subjects. Before​ treatment, 16 subjects had a mean wake time of 104.0 min. After​ treatment, the 16 subjects had a mean wake time of 98.2 min and a standard deviation of 22.8 min. Assume that the 16 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 104.0 min before the​ treatment? Does the drug appear to be​ effective? Construct the 95​% confidence interval estimate of the mean wake time for a population with the treatment. nothing minless thanmuless than nothing min ​(Round to one decimal place as​ needed.)

Answer 1

df = n - 1 = 16 - 1 = 15

t critical value at 0.05 level with 15 df = 2.131

95% confidence interval is

- t * S / sqrt(n) < < + t * S / sqrt(n)

98.2 - 2.131 * 22.8 / sqrt(16) < < 98.2 + 2.131 * 22.8 / sqrt(16)

86.1 <= <= 110.3

Since 104 contained in confidence interval , the drug does not appear to be effective,