Applying the Empirical Rule to a distribution with a mean of 80 and standard deviation of 5, which one of the following is correct?
A) About 34% of the values are located between 80 and 90.
B) About 95% of the values are between 70 and 90.
C) About 75% of the values are between 75 and 85.
D) All values fall between 65 and 95.

Question

Quizplus · Accepted Answer

The Empirical Rule states that for a normal distribution, approximately 68% of the data falls within one standard deviation of the mean, 95% within two standard deviations, and 99.7% within three standard deviations. Given a mean of 80 and a standard deviation of 5, two standard deviations from the mean (80 ± 2*5) gives the range 70 to 90, which encompasses about 95% of the data.

Applying the Empirical Rule to a Distribution with a Mean