A sample of 148 college students at a large university reports getting an average of 6.85 hours of sleep last night with a standard deviation of 2.12 hours. Suppose you want to conduct a similar study at your university. Assuming that the standard deviation of this sample is a reasonable estimate of the standard deviation of sleep time at your university, how many students do you need to survey to estimate the mean sleep time of students at your university with 95% confidence and a margin of error of 0.5 hours? Sample size needs to be 70 students. Sample size needs to be 85 students. Sample size needs to be 80 students. Sample size needs to be 75 students.
Added by Kristy W.
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96) Ļ = standard deviation (in this case, 2.12) E = margin of error (in this case, 0.5) Substituting the given values into the formula, we get: n = (1.96^2 * 2.12^2) / 0.5^2 n = (3.8416 * 4.4944) / 0.25 n = 17.222 / 0.25 n = 68.888 Since we can't have a fraction Show moreā¦
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