Assume a data set is normally distributed with mean 14 and standard deviation 1.5. If the data set contains 30 data values, approximately how many of the data values will fall within the range 12.5 to 15.5?
A) 13
B) 20
C) 29
D) 10

Question

Quizplus · Accepted Answer

Using the normal distribution, approximately 68% of the data values will fall within one standard deviation of the mean. Since the standard deviation is 1.5, 68% of the data values will fall within the range 14 +/- 1.5, or 12.5 to 15.5. Since the data set contains 30 data values, approximately 0.68 * 30 = 20 data values will fall within the range 12.5 to 15.5.

Assume a Data Set Is Normally Distributed with Mean 14