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 4.8 5.7 6.1 7.3 9.0 11.1 3.4 5.9 After 6.2 2.5 7.3 8.9 8.3 6.4 3.7 2.2 Construct a 95% confidence interval for the mean of the "before - after" differences.