Statistics help!

Question

In a test of the effectiveness of garlic for lowering cholesterol, 48 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 4.3 and a standard deviation of 15.8. Construct a 99% confidence interval estimate of the minute change in LDL cholesterol after the garlic treatment what does the confidence interval suggest about the effectiveness of garlic and reducing LDL cholesterol?

a. What is the best point estimate of the population mean net change in LDL cholesterol after the garlic treatment?

The best point estimate is 15.8 mg/dL. (Type an integer or a decimal.)

b. Construct a 99% 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?

? mg/dL ? < μ < ? mg/dL (Round to two decimal places as needed.)

What does the confidence interval suggest about the effectiveness of the treatment?

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

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

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

levels

D.The confidence interval limits contain 0, suggesting that the garlic treatment did affect the LDL cholesterol levels.

 

Answer 1

Let set up the confidence interval for the population mean. Then we have

[μ ± z*(σ/√n)] → [4.3 ± (2.576)(15.8/√48)] = [-1.575, 10.175]

We are 99% confident that the the minute change in LDL cholesterol after the garlic treatment is between -1.575 mg/dL and 10.175 mg/dL.

The answer woul be B. The confidence interval limits contain 0, suggesting that the garlic treatment did not affect the LDL cholesterol levels.