A study was conducted to measure the effectiveness of hypnotism in reducing pain. The measurements are centimeters on a pain scale before and after hypnosis. Assume that the paired sample data are simple random samples and that the differences have a distribution that is approximately normal. Construct a 95% confidence interval for the mean of the "before - after" differences. Does hypnotism appear to be effective in reducing pain? Before 8.4 2.4 11.7 8.2 7.2 10.1 3.7 3.2 After 6.1 2.1 7.9 8.3 8.5 6.4 3.4 2.4 Construct a 95% confidence interval for the mean of the "before - after" differences.