Researchers have studied the role that the age or workers has in determining the hours per month spent on personal tasks. a sample of 1,686 adults were observed for one month. the data are: age group 18-24 25-44 45-64mean 4.17 4.04 4.31std dev 0.75 0.81 0.82n 241 768 677construct a 95 percent confidence interval for the mean hours spent on personal tasks for 45-64 year olds.