Question

The Graduate Record Examination (GRE) has a combined verbal and quantitative mean of 1000 and a standard deviation of 200. Scores range from 200 to 1600 and are approximately normally distributed.
For each of the following problems:
1. Draw a rough sketch, darkening the portion of the cure that relates to the answer,
2. Indicate the percentage or score called for by the problem.

a. What percentage of persons who take the test score above 1300?
b. What percentage score above 800?
c. What percentage score below 1200?
d. Above what score do about 20 percent of the test-takers score?
e. Above what score do about 30 percent of the test-takers score

Answer 1

Cannot draw on these posts.

Z = (score-mean)/SD

a-c. Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportions/probabilities related to the Z scores. Multiply by 100.

d-e. Use same table for .20 and .30 to get Z scores. Insert in equation above to get raw score.