Normal Distribution Word Problems
1. A certain brand of flood lamps has a lifetime that is normally distributed with a mean of 3,750 hours and a standard deviation of 300 hours.
a) What is the probability that a lamp will last for more than 4,000 hours?
b) What is the probability that a lamp will last less than 3,000 hours?
c) What lifetime should the manufacturer advertise for these lamps in order that only 4% of the lamps will burn out before the advertised lifetime?