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 59 and a standard deviation of 3. Using the 68-95-99.7 rule, what is the approximate percentage of lightbulb replacement requests numbering between 59 and 62

Answer 1

About 34%

Explanation:

Given that :

Mean, m = 59 ; Standard deviation, s = 3

Bulb replacement numbering between 59 and 62

For, x = 59

Zscore = (x - m) / s

Z = (59 - 59) / 3 = 0

For x = 62

Z = (62 - 59) / 3 = 1

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

0.84134 - 0.5

= 0.34134

About 34%