Question 1169217: 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 min. After​ treatment, the 13 subjects had a mean wake time of 77.5 min and a standard deviation of 23.2 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 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.
please help. I've tried multiple different ways and all lead to the incorrect answer!
Answer by Boreal(15235)   (Show Source):
You can put this solution on YOUR website! The half-interval is t(0.95,df=12)*s/sqrt(13)
=1.782*23.2/sqrt (13)
=11.47 Add to and subtract from 77.5 min
the interval is (66.03, 88.97) min
Since 100 min Ho is outside the interval, the drug appears to be effective.
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