Question

In a test of the effectiveness of garlic for lowering​ cholesterol, 47 subjects were treated with garlic in a processed tablet form. Cholesterol levels were measured before and after the treatment. The changes ​(beforeminus​after) in their levels of LDL cholesterol​ (in mg/dL) have a mean of 5.5 and a standard deviation of 15.6. 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? Click here to view a t distribution table.LOADING... Click here to view page 1 of the standard normal distribution table.LOADING... Click here to view page 2 of the standard normal distribution table.LOADING... What is the confidence interval estimate of the population mean mu​? nothing ​mg/dLless thanmuless than nothing ​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 contain ​0, suggesting that the garlic treatment did not affect the LDL cholesterol levels.

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

Answer 1

Refer t-table or use excel function "=T.INV.2T(0.05,46)" to find the value of t.

If the confidence interval limits contain 0, it is very possible that the mean net change in LDL cholesterol is equal to 0, suggesting that the garlic treatment did not affect the LDL cholesterol levels, If the lower confidence interval limit is greater than 0, this suggests that the garlic treatment may be effective.