Question

9. In a large discount store, the maintenance department has been instructed to replace all of the light bulbs at the same time. Past experience indicates that the lives of light bulbs are normally distributed with a mean life of 1200 hours and standard deviation of 100 nours. When should the liehts be repleed so that no more than 7.5% burned due the gram for normal distribution, define the time of bulb replacement that separates ns hattom 7.5% and circle one of the multiple choice answers. (6 points) -5- D) 1180 C) 1056 B) 1126 A) 1344