Assume the scores on ACT test for last year's high school graduating class had mean 20.9 and standard deviation 4.8. In all, 1,163,490 students in this class took the test, and 1,043,457 of them had scores of 28 or lower.
If the distribution of scores were Normal, what percent (±0.1) of scores would be 28 or lower?
What percent (±0.1) of the actual scores were 28 or lower?