statistics
posted by Rhi .
A manufacturer knows that their items have a normally distributed length, with a mean of 7.3 inches, and standard deviation of 0.6 inches.
If one item is chosen at random, what is the probability that it is less than 5.5 inches long?

Z = (scoremean)/SD
Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion/percentage related to the Z score.