Use the 68-95-99.7 rule to solve the problem.
-Scores on a test are normally distributed with a mean of 101 and a standard deviation of 20. What percentage of scores are greater than 161?
A)99.85%
B)99.7%
C)0.3%
D)0.15%

Question

Quizplus · Accepted Answer

According to the 68-95-99.7 rule (or the empirical rule), 99.7% of data within a normal distribution falls within three standard deviations of the mean. Since 161 is three standard deviations above the mean (101 + 3*20 = 161), 0.15% of scores are greater than 161 (100% - 99.85% = 0.15%).

Use the 68-95-99.7 Rule to Solve the Problem