Use the Empirical Rule to Describe Data That Are Bell Shaped
-The average score of local students on a college entrance exam is 110 , with a standard deviation of 5 . The distribution is roughly bell shaped. Use the Empirical Rule to find the percentage of local students with scores above 120 .
A) $2.5 \%$
B) $5 \%$
C) $95 \%$
D) $97.5 \%$

Question

Quizplus · Accepted Answer

According to the Empirical Rule for a bell-shaped distribution, approximately 68% of data falls within one standard deviation of the mean, 95% within two standard deviations, and 99.7% within three standard deviations. A score of 120 is two standard deviations above the mean (110 + 2*5). Therefore, 95% of scores fall below 120, leaving 5% above it. However, since this includes both tails and the question asks for the percentage above 120 only, we divide that 5% by 2, resulting in 2.5%.

Use the Empirical Rule to Describe Data That Are Bell 2.5%2.5 \%2.5%

Use the Empirical Rule to Describe Data That Are Bell $2.5 \%$