Use the empirical rule to solve the problem.
-The amount of Jen's monthly phone bill is normally distributed with a mean of $55 and a standard deviation of $12. What percentage of her phone bills are between $19 and $91?
A) 99.7%
B) 99.99%
C) 95%
D) 68%

Question

Quizplus · Accepted Answer

The empirical rule states that 99.7% of data in a normal distribution lies within three standard deviations from the mean. Here, $19 and $91 are three standard deviations below and above the mean ($55 ± 3*$12), so 99.7% of the bills fall within this range.

Use the Empirical Rule to Solve the Problem