D 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 After 10.5 2.1 6.2 2.3 10.3 8.2 9.0 8.0 7.8 8.3 8.9 6.9 2.0 3.1 1.8 2.4 Construct a 95% confidence interval for the mean of the "before-after" differences. Ha (Round to two decimal places as needed.)