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 10.8 6.9 6.7 12.3 12.4 8.4 6.1 5.2 After 6.3 2.8 7.3 8. 8.1 6.1 3.6 2.4 Construct a 95% confidence interval for the mean of the "before - after" differences.