For a normal distribution curve with a mean of 15 and a standard deviation of 5, which range of the variable defines an area under the curve corresponding to a probability of
Approximately 68%?
A) from 10 to 20
B) from 5 to 25
C) from 15 to 25
D) from 12.5 to 17.5

Question

Quizplus · Accepted Answer

The 68-95-99.7 rule for a normal distribution states that approximately 68% of the data falls within one standard deviation of the mean. Given a mean of 15 and a standard deviation of 5, one standard deviation below the mean is 10 (15-5) and one standard deviation above the mean is 20 (15+5), making the range from 10 to 20.

For a Normal Distribution Curve with a Mean of 15