A clinical trial was conducted to test the effectiveness of a drug used for treating insomnia in older subjects. After treatment with the drug, 15 subjects had a mean wake time of 90.7 min and a standard deviation of 44.9 min. Assume that the 15 sample values appear to be from a normally distributed population and construct a 90% confidence interval estimate of the standard deviation of the wake times for a population with the drug treatments. Does the result indicate whether the treatment is effective?
At 90% confidence interval the critical values are
=
= 23.6848
=
= 6.5706
The 90% confidence interval for population standard deviation is
sqrt((n - 1)s^2/)
<
< sqrt((n - 1)s^2/
)
= sqrt(14 * (44.9)^2/23.6848) <
< sqrt(14 * (44.9)^2/6.5706)
= 34.52 <
< 65.54
Get Answers For Free
Most questions answered within 1 hours.