In a test for effectiveness of garlic for lowering cholesterol, 47 subjects were treated with Garlicin. 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 standard deviation of of 15.7
Construct a 95% confidence interval estimate of the mean net change of LDL, cholesterol after the Garlicin treatment.