Interval	Frequency
The lives (in hours of continuous use) of 100 randomly selected flashlight batteries are:	6.957.45	2
7.457.95	8
7.958.45	19
8.458.95	37
8.959.45	20
9.459.95	11
9.9510.45	3

a. Find the mean of the battery lives.

(Type an integer or a decimal. Round to two decimal places.)

b. Find the standard deviation of the battery lives.

(Type an integer or a decimal. Round to two decimal places.)