problem 1. (12 points) light bulbs of a certain type are advertised as having an average lifetime of 800 hours. the price of these bulbs is very favorable, so a potential customer has decided to go ahead with a purchase arrangement unless it can be conclusively demonstrated that the true average lifetime is smaller than what is advertised. a random sample of 50 bulbs was selected, the lifetime of each bulb determined, and the appropriate hypotheses were tested, resulting in the accompanying output: variable n mean st. dev se of mean z p-value lifetime 50 738.44 38.20 5.40 -2.14 0.016 a) what conclusion would be appropriate for a significance level of .05? b) what about at a significance level of .01? c) which significance level would you recommend? why?