Question: A sample 200 students in a Stat class were asked “How long did you sleep last night?” The results are found below.

sample mean = 6.4 hours

S.D. = 1.6 hours

standard error (S.E.) = .11 hours

sample size (n) = 200

a. Set up the calculation of a 95% confidence interval to estimate the population mean number of hours slept last night?

b. Knowing that the margin of error = .22, write out a one-sentence interpretation of the margin of error.

c. The 95% confidence interval to estimate the population mean number of hours slept last night is (6.18 to 6.62) hours. Write out a one-sentence interpretation of this confidence interval.

d. What type of data is used in this example?

e. What would happen to the size of the margin of error or confidence interval if the level of confidence were instead 68%? Explain