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The IQ scores for a random sample of subjects with low n X S lead levels in their blood and another random sample of Low Lead Level #1 88 91.89148 15.45902 subjects with high lead levels in their blood were collected. The statistics are summarized in the accompanying table. High Lead Level H2 28 87.70305 8.18115 Assume that the two samples are independent simple random samples selected from normally distributed populations. Do not assume that the population standard deviations are equal. Complete parts (a) to (c) below. . . . a. Use a 0.01 significance level to test the claim that the mean IQ score of people with low blood lead levels is higher than the mean IQ score of people with high blood lead levels.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 11.0 1.3 7.7 11.6 6.7 6.9 2.9 4.6 After 6.6 2.8 7.8 8.1 8.6 6.3 3.6 2.8 C. . . Construct a 95% confidence interval for the mean of the "before - after" differences.