Question

A clinical trial was conducted to test the effectiveness of the drug zopiclone for treating insomnia in older subjects. Before treatment with zopiclone, 20 subjects had a mean wake time of 103.0 minutes. After treatment with zopiclone, the 20 subjects had a mean wake time of 74.4 minutes and s standard deviation of 23.3 minutes. Assume that the 20 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 zopiclone treatments. What does the result suggest about the mean wake time of 103.0 minutes before the treatment? Does zopiclone appear to be effective?

Construct the 99​% confidence interval estimate of the mean wake time for a population with the treatment.  

____min<u<______min

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

What does the result suggest about the mean wake time of 103.0 min before the​ treatment? Does the drug appear to be​ effective?

The confidence interval (includes or not include) which one the mean wake time of 103.0 min before the​ treatment, so the means before and after the treatment are (different or could be the same )which one

Answer 1

Solution :

degrees of freedom = n - 1 = 20 - 1 = 19

t/2,df = t0.005,19 = 2.861

Margin of error = E = t/2,df * (s /n)

= 2.861 * ( 23.3/ 20)

Margin of error = E = 14.9

The 99% confidence interval estimate of the population mean is,

- E < < + E

74.4 - 14.9 < < 74.4 + 14.9

( 59.5 min. < < 89.3 min.)

The confidence interval does not include the mean wake time of 103.0 min.before the treatment so the means before and after the treatment are different  this result suggests that the drug treatment has a significant effect