In a test of the effectiveness of garlic for loweringcholesterol, 50 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 3.3 and a standard deviation of 17.8.

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 LDLcholesterol?

What is the confidence interval estimate of the population mean ?

Round two decimal places as needed.