Question

The maintenance department at the main campus of a large state university receives daily requests to replace fluorecent lightbulbs. The distribution of the number of daily requests is bell-shaped and has a mean of 39 and a standard deviation of 10. Using the 68-95-99.7 rule, what is the approximate percentage of lightbulb replacement requests numbering between 29 and 39?

Enter your answer as an integer or decimal number

Answer 1

Solution :

Given that ,

mean = =39

standard deviation = = 10

P(29< x < 39) = P[(29- 39) /10 < (x - ) / < (39 - 39 ) /10 )]

= P( -1< Z < 0)

= P(Z <0)+P(Z <-1 )

using empirical rule

=0%/2 + 68%/2

=0%+34%

=34%