Question

The lifetime of bulbs produced by Tariqs lightening company follows a normal distribution with a mean of 3462 hours and a standard deviation 1070 hours. What is the probability that randomly selected bulb will have a lifetime of at most 2800?

Answer 1

We use Z calculations

Z(2800) = (2800 - 3462)/ 1070

= -0.618691588

The area to the left of the Z score is equal to 0.26763 which is the probability that a randomly selected bulb will have a lifetime of atmost 2800.