An Accelerated Life Test on a Large Number of Type-D

An accelerated life test on a large number of type-D alkaline batteries revealed that the mean life
For a particular use before they failed is 19.0 hours. The distribution of the lives approximated a
Normal distribution. The standard deviation of the distribution was 1.2 hours. About 95.44 percent of
The batteries failed between what two values?

A) 8.9 and 18.9
B) 12.2 and 14.2
C) 14.1 and 22.1
D) 16.6 and 21.4