Suppose that the lifetimes of light bulbs are approximately normally distributed, with a mean of 57 57 hours and a standard deviation of 3.5 3.5 hours. With this information, answer the following questions. (a) What proportion of light bulbs will last more than 61 61 hours?
Suppose that the
lifetimes of light bulbs are approximately normally distributed, with a mean of 57
57 hours and a standard deviation of 3.5
3.5 hours. With this information, answer the following questions.
(a) What proportion of light bulbs will last more than 61
61 hours?
(b) What proportion of light bulbs will last 53
53 hours or less?
(c) What proportion of light bulbs will last between 59
59 and 62
62 hours?
(d) What is the probability that a randomly selected light bulb lasts less than 45
45 hours?