# Duracell batteries claim that their AA size batteries have an average life longer than 15 hours*.

Duracell batteries claim that their AA size batteries have an average life longer than 15 hours*. A sample of 9 mechanical boxing kangaroos is tested using the Duracell batteries with the following life times recorded in hours:

**16.5**

**14.8**

**15.3**

**16.8**

**14.8**

**14.6**

**15.9**

**16.1**

**14.7**

It is known from past test records that the lifetime of Duracell AA battery is normally distributed with a standard deviation (s) of 0.6 hour. Based on the above information, test Duracell’s claim allowing for a probability of a Type I error of 1% using:

(a) the p-value approach, and,(b) the critical value approach