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 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 10.8 3.6 11.4 13.0 11.5 9.2 3.8 5.5 After 6.9 2.3 7.5 8.9 8.7 6.8 3.3 2.9 Construct a 95% confidence interval for the mean of the "before - after" differences.