In a test of the effectiveness of garlic for lowering cholesterol, 47 adult subjects were treated with Garlicin, which is 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 an average (mean) of 3.2 (based on data from "Effect of Raw Garlic vs Commercial Garlic Supplements on Plasma Lipid Concentrations in Adults With Moderate Hypercholesterolemia," by Gardner et al, Archives of Internal Medicine, Vol. 167).
Identify the sample, the population, the sample statistics and the population parameter.