posted by jamie on .
In a time-use study, 20 randomly selected managers were found to spend a mean of 2.40 hours each day on paperwork. The standard deviation of the the 20 scores is 1.30. Also, the sample data appear to have a bell-shaped distribution. Construct the 95% confidence interval for the mean time spent on paperwork by all managers.
CI95 = mean ± 1.96(sd/√n)
mean = 2.40
sd = 1.30
n = 20
Plug the values into the formula and calculate the interval.
I hope this will help get you started.