Question

The battery life of a fully charged cell phone is normally distributed, with a mean of 14 hours and a standard deviation of 2 hours. What is the probability that a randomly selected cell phone will have a battery life of at least 8 hours

Answer 1

.0013

Explanation:

8 hours is 3 standard deviations BELOW the mean z-score = -3

from z scor table , tis corresponds to .0013