In a test of the effectiveness of garlic for lowering choles

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 in their levels of LDL cholesterol (in mg/dL) have a mean of 5.5 and a standard deviation of 16.7.

Complete part (b) below.

Construct a 90% 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 ?

­­­_________mg/dL < < ________?

Solution

ME = 1.645*16.7/sqrt(43) = 4.189
90% C.I:
5.5 - 4.189 < u < 5.5 + 4.189
1.311 < u < 9.689

The confidence interval limits do not contain 0,suggesting that the garlic treatment did affect the LDL cholesterol levels.