posted by Huffette .
A set of 50 data values has a mean of 48 and a variance of 9.
I. Find the standard score (z) for a data value = 43.
II. Find the probability of a data value < 43.
Z = (score-mean)/SD
SD = √variance
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.
Indicate your subject in the "School Subject" box, so those with expertise in the area will respond to the question. You lucked out this time.