The lifetime of a randomly chosen battery in a certain application is modeled by a normal distribution with mean µ = 16 hours and standard deviation ? = 2 hours.
(a) Give one reason why the normal distribution may not be appropriate for this problem.
(But let's assume it anyway in the calculations below.)
(b) What is the probability that a battery will last more than 18 hours?
(c) What is the probability that the lifetime of a battery is between 12 and 17 hours?
(d) Find the number t such that the probability that a battery lasts less than t hours is 0.10.