Part A: A clinic measured the systolic blood pressure for a random sample of 10 patients. The resulting 95% confidence interval for the mean systolic blood pressure of all the patients at this clinic was (111.3, 129.5). What was the margin of error for this confidence interval?
9.1
18.2
120.4
240.8
Part B: Twenty-four pairs of adult brothers and sisters were sampled at random from a population. The difference in heights, recorded in inches (brother's height minus sister's height), was calculated for each pair. The 95% confidence interval for the mean difference in heights for all brother-and-sister pairs in this population was (-0.76, 4.34). What was the sample mean difference from these 24 pairs of siblings?
-0.76 inches
0 inches
1.79 inches
4.34 inches