posted by Jen on .
A set of 50 data values has a mean of 18 and a variance of 4.
I. Find the standard score (z) for a data value = 20.
II. Find the probability of a data value < 20.
Z = (score-mean)/SD
Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion related to the Z score.