Question

A clinical trial was conducted to test the effectiveness of a drug for treating insomnia in older subjects. Before​ treatment,19

subjects had a mean wake time of

104.0 min. After​ treatment, the 19

subjects had a mean wake time of 94.8 min and a standard deviation of 24.5 min. Assume that the 19

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

104.0104.0

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.

nothing

minless than<muμless than<nothing

min

​(Round to one decimal place as​ needed.)

Answer 1

n=19, = 94.8, s= 24.5, c=99%

formula for confidence inteval is

Where tc is the t critical value for c=99% with df=n-1 = 19-1 =18

using t table we get

tc = 2.878

94.8 − 16.179 <    < 94.8 + 16.179

78.6 <    < 111.0

the mean wake time before the​ treatment is = 104 minute

here, 104 lies beween our confidence inteval 78.6 to 111.0.

Hence, drug is not effective.

No, the confidence interval indicates that the drug is NOT effective because the interval contain 104 minutes.