Question

A data set is normally distributed with a mean of 42 and a standard deviation of 9. What percent of the data values lie between 15 and 60?

Answer 1

97.59%.

Explanation:

z-score for data value 15 = (15-42) / 9

= -3.

z-score for data value (60 - 42) /9

= 2.

Using the standard normal tables we get:

= 0.4772- ( - 0.4987)

= 0.9759.