Asked by Anonymous

if there are 145 test questions, and the mean of the test scores for a class is 100 with a standard devation of 15, what percentage of the people taking the test would have the following scores: scored b/w 100 &115, scored b/w 100 & 115,scored b/w 0 & 100, scored b/w 0 & 145, or scored b/w 0 &85?
Answered by PsyDAG
Z = (score-mean)/SD

Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportions related to the Z scores.