please just help with 7.21 other questions are just for reference

7.39. Arch Supports Problems and m report on a. study of 64 older adults to investigate the effectiveness of arch supports in relieving pain. For paired differences calculated as: d = :31 a:2, where 171 is the pre-support pain score and 1:2 is the post-support pain score, the mean and standard deviation of the paired differences are: d = 1.45 and sd = 2.30. Answer the questions for a 95% condence interval on the population mean of the paired differences. (a) Describe the population under study. (b) Find the statistic. (c) Find the confidence level multiplier. (d) Find the standard error. (e) Find the margin of error. (f) Find the lower limit and upper limit of the confidence interval. (g) Interpret the confidence interval in the context of the problem.(c) what is the blocking variable on which we pair? (d) What is the explanatory variable? 7.9. Arch Supports A study by Mulford et al. (2008) investigated if arch support improves balance and alleviates pain in older adults. [72] Quoting from the paper, A convenience sample of older adults formed a single group for fitting with arch supports. Balance, functional mobility, and self-reported pain in the back and lower extremities were measured without the arch supports. . . and after 6 weeks of arch support use. (a) Why is this paired data instead of independent (2-samples) data? (b) What are the blocks? (c) What is the explanatory variable?7.21. Arch Supports Problem described a study on the effectiveness of arch supports in older adults. (a) The heading of Table 4 in the paper is \"Pain score mean values by location and time ) interval [before the intervention (pre) and 6 weeks after the arch support treatment (post)].\" The paper reports the pre mean as 4.33, the post mean as 2.88, and the paired differences mean as 1.45. How were the paired dierences d calculated? 0)) Pairing was effective at reducing the variation by about 33%. It is not surprising that pairing would be effective in this situation. Why