A new drug to treat high cholesterol is being tested by phar

A new drug to treat high cholesterol is being tested by pharmaceutical company. The cholesterol levels for 20 patients were recorded before administering the drug and after. The 90% confidence interval for the true mean difference in total cholesterol levels (after - before) was (-32.14, 17.63).

Which of the following is the appropriate conclusion?

A. We are 90% confident that the average difference in cholesterol levels is negative, with the higher cholesterol levels being before the drug regimen.

B. We are 90% confident that the average difference in cholesterol levels is positive, with the higher cholesterol levels being before the drug regimen.

C. We are 90% confident that the average difference in cholesterol levels is negative, with the higher cholesterol levels being after the drug regimen.

D. There is not a significant difference in cholesterol levels before and after the drug.

E. We are 90% confident that the average difference in cholesterol levels is positive, with the higher cholesterol levels being after the drug regimen.

Solution

Interpretations:
1) We are 9o% sure that the interval [-(-32.14, 17.63)] contains the difference between
true population proportion P1-P2
2) If a large number of samples are collected, and a confidence interval is created
for each sample, 90% of these intervals will contain the difference between true
population proportion P1-P2
3) Since this Cl does contain zero, we can conclude at ( = 0.05 that true mean
difference is zero.

ANS:

C. We are 90% confident that the average difference in cholesterol levels is negative, with the higher cholesterol levels being after the drug regimen.