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 13.4 9.2 After 6.9 2.3 2.2 8.9 8.5 6.3 2.4 Construct a 95% confidence interval for the mean of the "before - after" differences. 12