The average score of local students on a college entrance exam is 110, with a standard deviation of 5. Thedistribution is roughly bell shaped. Use the Empirical Rule to find the percentage of local students with scoresabove 120.
A) 2.5%
B) 5%
C) 95%
D) 97.5%

Question

Quizplus · Accepted Answer

A score of 120 is two standard deviations above the mean (110 + 2*5 = 120). According to the Empirical Rule, 95% of the data falls within two standard deviations of the mean, leaving 5% outside. Since the distribution is symmetrical, 2.5% is above 120 and 2.5% is below 100.

The Average Score of Local Students on a College Entrance