Engineering Economy 7th Edition by Leland Blank ,Anthony Tarquin

Exercise 21

There are four estimates made for the anticipated cycle time to produce a subcomponent. The estimates, in seconds, are 10, 20, 30, and 50.
a) If equal weight is placed on each estimate, what is the expected cycle time (b) If the largest time is disregarded, what is the percent reduction in the expected time