Question
The physical plant at the main campus of a large state university receives daily requests to replace florecent lightbulbs. The distribution of the number of daily requests is bell-shaped and has a mean of 42 and a standard deviation of 10. Using the empirical rule (as presented in the book), what is the approximate percentage of lightbulb replacement requests numbering between 22 and 42?
Answers
PsyDAG
22 is two SD below the mean, in other words, Z = -2.
Z = (score-mean)/SD
Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion/probability related to the Z score and distance from the mean. Multiply by 100.
Z = (score-mean)/SD
Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion/probability related to the Z score and distance from the mean. Multiply by 100.