e lifetime of a 2-volt non-rechargeable battery in constant use has a normal distribution with a mean of 516 hours and a standard deviation of 20...

e lifetime of a 2-volt non-rechargeable battery in constant use has a normal distribution with a mean of 516 hours and a standard deviation of 20 hours. You take a random sample of four 2-volt non-rechargeable batteries. What is the probability that their average lifetime would be less than 510 hours? Use your calculator to solve this problem and give your answer as a number between 0 and 1, rounded to 3 decimal places.