Assume that a set of test scores in an Introduction to Finance class is normally distributed with a mean of 72 and a standard deviation of 8.Use the 68-95-99.7 rule to find the percentage of scores greater than 88.
A)0.15%
B)0.3%
C)2.5%
D)5%
E)95%

Question

Quizplus · Accepted Answer

According to the 68-95-99.7 rule (or the empirical rule), approximately 95% of the data in a normal distribution falls within two standard deviations of the mean. Since the mean is 72 and the standard deviation is 8, two standard deviations above the mean is 72 + 2(8) = 88. Therefore, 95% of the scores are below 88, leaving 5% of the scores above 88. However, this 5% is split between the two tails of the distribution, so only 2.5% of the scores are greater than 88.

Assume That a Set of Test Scores in an Introduction