Question

In a test of the effectiveness of garlic for lowering​ cholesterol,43 subjects were treated with garlic in a processed tablet form. Cholesterol levels were measured before and after the treatment. The changes ​(before​after) in their levels of LDL cholesterol​ (in mg/dL) have a mean of 5.7 and a standard deviation of 15.2. Construct a ​95% confidence interval estimate of the mean net change in LDL cholesterol after the garlic treatment. What does the confidence interval suggest about the effectiveness of garlic in reducing LDL​ cholesterol?

What is the confidence interval estimate of the population mean μ​?

Answer 1

(a)

n = Sample Size = 43

= Mean of difference d = Before -After = 5.7

s_d = Standard Deviation of difference d = Before -After = 15.2

= 0.05

df = 43 - 1 = 42

From Table, citical values of t = 2.018

Confidence Interval:

So,

Answer is:

(1.022, 10.378)

(b)

Since all values in the confidence interval: (1.022, 10.378) are positive,we conclude:

The garlic is effective in reducing LDL​ cholesterol.