A clinical trial is run comparing a new drug for high cholesterol to a placebo. A total of 40 participants are randomized (with equal assignment to treatments) to receive either the new drug or placebo. Their total serum cholesterol levels are measured after eight weeks on the assigned treatment. Participants receiving the new drug reported a mean total serum cholesterol level of 209.5 (std dev = 21.6) and participants receiving the placebo reported a mean total serum cholesterol level of 228.1 (std dev = 19.7).
1. Construct a 95% confidence interval for the difference in mean total serum cholesterol levels between participants receiving the new drug versus placebo.
2. Is the new drug effective? Justify briefly.