Question

A clinical trial was conducted tot est the effectiveness of a drug treating insomnia in older subjects. Before treatment, 24 subjects had a mean wake time of 101.0 min. After treatment, the 24 subjects had a mean wake time of 94.2 min and a standard deviation of 23.7 min. Assume that the 24 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 101.0 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. They want the critical range values.

Answer 1

Given Information:

Mean wake time before treatment = 101.0 minute

Mean wake time after treatment = 94.2 minute

Standard Deviation = 23.7 minute

Sample size = 24

Following formula can be used to calculate the confidence interval

df = n-1

where n = sample size

df = 24-1 =23

The value of t score at 95% confidence level and df = 23 is 2.069

The negative value of LCL suggests that the mean wake time after treatment can go beyond the mean wake time before the treatment.

Thus the drug does not appear to be much effective,