Question

A production manager has measured the lifetimes of 10 lightbulbs. The lifetimes she measured are 342, 375, 398, 412, 423, 450, 457, 493, 502, and 568 hours. She calculates the mean of these numbers. What is the mean lifetime?

Answer 1

Mean µ = ∑x/n

Answer 2

i think you add them all together and then divide them by 10. but that seems way to simple

Answer 3

So...442??