In a time-use study, 58 randomly selected managers were found to spend a mean of 3.56 h each day on paperwork. The population standard deviation is known to be about 1.53 h. Construct the 95 % confidence interval for the mean time spent on paperwork by all managers.

Round thez

z

-value to 3 decimal places and the confidence interval values to 2 decimal places.

For part (a), use a positivez

z

-value.

(a) What is the criticalz

z

-value that will need to be used to calculate the confidence interval?

(b) What is the 95% confidence interval?