Question

7.2.9-T Question Help Here are summary statistics for randomly selected weights of newborn girls: n = 181, x = 29.4 hg, s = 6.4 hg. Construct a confidence interval estimate of the mean. Use a 98% confidence level. Are these results very different from the confidence interval 28.3 hg <3 <31.1 hg with only 17 sample values, X = 29.7 hg, and s = 2.3 hg? What is the confidence interval for the population mean? ng << ng (Round to one decimal place as needed.) Enter your answer in the edit fields and then click Check Answer part remaining Clear All Check Answer

Answer 1

Excel add-in (Mega Stat) procedure: Step 1: In EXCEL, Select Add-Ins > Mega Stat> Confidence intervals/Sample size. Step 2: Choose Confidence intervals-Mean Step 3: Enter 29.4 as the mean, 6.4 as the Std. Dev, and 181 as the n. Step 4: Chooset Step 4: In Confidence Level, Choose 98% Step 5: Click Preview and then OK Excel add-in (Mega Stat) output Confidence interval mean 98% confidence level 29.4 mean 6.4 std. dev. 181 n 2.347 t (df 180) 1.117 half-width 30.517 upper confidence limit 28.283 lower confidence limit The 98% confidence interval is 28.3hg <30.5hg No, these results are not very different from the confidence interval 28.3hg < u<31.1hg