In a test of the effectiveness of garlic for lowering cholesterol, 49 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 2.9 and a standard deviation of 18.4.
What is the best point estimate of the population mean net change in LDL cholesterol after the garlic treatment?
The best point estimate is______mg/dL.
(Type an integer or a decimal.)