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 46 and a standard deviation of 9. Using the empirical rule (as presented in the book), what is the approximate percentage of lightbulb replacement requests numbering between 46 and 73?

Answer 1

Z = (score-mean)/SD = (73-46)/9 = ?

Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion/probability between mean and that Z score.