1. A manufacturer claims that its light bulbs have a mean life of 600 hours and a standard deviation of 80 hours. Assume that the distribution of the population is a normal distribution . Round your z -scores to 2 decimal places during your calculations , then Round probability answers to 4 decimal places. a ) If you just purchased one light bulb what is the probability that the lifetime of the light bulb is greater than 625 hours ? b) If you purchased 35 light bulbs, what is the probability that mean lifetime for these 35 light bulbs is greater than 625? c) How are the answers going to change in parts (a) and (b ) if we do not assume that the lifetime is normally distributed