For a normal distribution curve with a mean of 15 and a standard deviation of 3, which range of the variable defines an area under the curve corresponding to a probability of approximately 68%?
A) from 13.5 to 16.5
B) from 12 to 18
C) from 15 to 21
D) from 9 to 21

Question

Quizplus · Accepted Answer

In a normal distribution, approximately 68% of the data falls within one standard deviation of the mean. Here, the mean is 15 and the standard deviation is 3, so the range is from 12 (15-3) to 18 (15+3).

For a Normal Distribution Curve with a Mean of 15