Suppose the mean hours slept (per day) among a sample of college students was 7.1, and a 95% confidence interval for the population mean hours slept was constructed. Which one of these could it be?
Suppose that based on a random sample, a 95% confidence interval for the mean hours slept (per day) among graduate students was found to be (6.5, 6.9). What is the margin of error of this confidence interval?