What duration should be used in your schedule if you want to ensure 95% confidence that the activity’s duration will not be exceeded?

Scheduling and Planning

Historic records show that the mean duration of an activity is expected
to be 8 days with a standard deviation of 2.4 days.

a) What duration should be used in your schedule if you want to ensure 95% confidence that the activity’s duration will not be exceeded?

b) What it the probability that the duration will actually exceed 10 days?