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how to solve the problem when on 100 point examination with mean 60, SD 10, if there are 5% A, 5% F, 15% B, 15% D, and 60% C, find the scores that devide the distribution into those catagories.
Z = (score-mean)/SD
Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the Z scores related to the given proportions. Substitute those values in the equation above.
Remember that the top D grade includes the cumulative percentage of both D and F grades. C = middle 60% (±30%).