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11 Find the margin of error for u, if n = 18, s = 12, and c = .90. 12 Construct the confidence interval for u using: x-bar = 88.8 and E = 18.3 13 In a survey of college professors, 1,234 have at least two credit cards, but 432 do not have any. Find p-hat and q-hat, if p is the proportion of the population who have at least two credit cards. 14 Construct the Confidence Interval for p if q-hat = .354 and n = 2,000. (Use Zc = 1.28) 15 Find the critical values Chi-Square Sub L and Chi-Square Sub R needed to estimate sigma squared if n = 17 and alpha = .10