question archive 1) The Bright Light Company tested a new line of photographic bulbs and found their lifetimes to be normally distributed with a mean lifetime of 98 hours and a standard deviation of 13 hours
Subject:StatisticsPrice: Bought3
1) The Bright Light Company tested a new line of photographic bulbs and found their lifetimes to be normally distributed with a mean lifetime of 98 hours and a standard deviation of 13 hours.
a) What percent of the bulbs last between 72 and 124 hours?
b) What is the probability that a randomly selected bulb will last more than 111 hours?
c) In a shipment of 1200 bulbs, how many would you expect to have a lifetime of less than 76 hours?