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 8.2 4.0 5.8 7.6 9.2 5.8 7.8 2.4 After 6.3 2.1 7.6 8.1 8.5 6.7 3.9 2.3 Construct a 95% confidence interval for the mean of the "before - after" differences