The College Board originally scaled SAT scores so that the scores for each section were approximately normally distributed with a mean of 500 and a standard deviation of 100. Assuming scores follow a bell-shaped distribution, use the empirical rule to find the percentage of students who scored less than 400.
A)16%
B)68%
C)84%
D)32%

Question

Quizplus · Accepted Answer

According to the empirical rule (or 68-95-99.7 rule) for a normal distribution, approximately 68% of the data falls within one standard deviation of the mean. Since the mean is 500 and the standard deviation is 100, scores from 400 to 600 encompass approximately 68% of students. Therefore, half of the remaining 32% (which is not within one standard deviation) would score below 400, which is 16%.

The College Board Originally Scaled SAT Scores So That the Scores