in a test of the effectiveness of garlic for lowering cholesterol , 50 subjects were treated with garlic in a processed tablet form. Cholesterol levels were measured before and after treatment. The changes in their levels of LDL cholesterol have a mean of 5.5 and a standard deviation of 19.6. What is the best point estimate of the population mean net changes in LDL cholesterol after the garlic treatment? 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?