Suppose the life of a particular brand of calculator battery is approximately normally distributed with a mean of

85

85 hours and a standard deviation of

9

9 hours. Complete parts a through c.

Question content area bottomPart 1

a. What is the probability that a single battery randomly selected from the population will have a life between

80

80 and

90

90 hours?

P(

80

80

less than or equals

x overbar

x

less than or equals

90

90)

equals

=

enter your response here

(Round to four decimal places as needed.)