Question

Suppose that the lifetimes of light bulbs are approximately normally​ distributed, with a mean of 56 hours and a standard deviation of 3.3 hours. With this​ information, answer the following questions.

(a) What proportion of light bulbs will last more than 61​hours?

​(b) What proportion of light bulbs will last 51 hours or​ less?

​(c) What proportion of light bulbs will last between 57 and 62 hours?

​(d) What is the probability that a randomly selected light bulb lasts less than 46 hours?

Answer 1