Use the empirical rule to solve the problem.
-The amount of Jen's monthly phone bill is normally distributed with a mean of $73 and a standard deviation of $9. What percentage of her phone bills are between $46 and $100?
A)95.44%
B)99.74%
C)99.99%
D)68.26%

Question

Use the empirical rule to solve the problem.
-The amount of Jen's monthly phone bill is normally distributed with a mean of $73 and a standard deviation of $9. What percentage of her phone bills are between $46 and $100? 
A)95.44%
B)99.74%
C)99.99%
D)68.26%

Quizplus · Accepted Answer

The empirical rule, or 68-95-99.7 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. The range from $46 to $100 is from three standard deviations below the mean ($73 - 3*$9 = $46) to three standard deviations above the mean ($73 + 3*$9 = $100). Therefore, according to the empirical rule, approximately 99.74% of Jen's phone bills are between $46 and $100.

Use the Empirical Rule to Solve the Problem