I have a question about 1.f. I cannot get the answer 0.7928919. I think the code is correct. Which is not correct, the code or the answer? Thanks,

1. The lifetime of a certain type of light bulb has a Normal distribution with = 2000 hours and = 200 hours. Let represent the number of hours a randomly chosen light bulb lasts.

f. Let represent the total combined lifetime of 6 independent light bulbs. Find (<12,300).