A study measured the LDL cholesterol level in 49 subjects. The subjects were then treated with raw garlic for six months. The mean change in the 49 subjects was a reduction of 0.4 with a standard deviation of 21.0 (assume this is the actual standard deviation for the population, not an estimate). a. Find a 95% confidence interval for the mean change in LDL cholesterol after a treatment of garlic. b. Looking at the confidence interval, do you think garlic is effective in reducing LDL cholesterol? Explain.