There is a large supply of light bulbs with the average life of 1000 hours and the standard deviation of 50 hours. A light bulb is drawn at random. Find the probability that it will last more than...

There is alarge supply of light bulbs with the average life of1000 hours and the standard deviation of50 hours.

1. A light bulb is drawn at random. Find the probability that it will lastmore than 1020 hours.


2. A random sample of25 light bulbs is drawn. Find the probability that thesample average life ismore than 1020 hours.