Chapter 6.1, Problem 47BSC

Basis for the Range Rule of Thumb and the Empirical Rule. In Exercises 45–48, find the indicated area under the curve of the standard normal distribution; then convert it to a percentage and fill in the blank. The results form the basis for the range rule of thumb and the empirical rule introduced in Section 3-2.

47. About __________ % of the area is between z = −3 and z = 3 (or within 3 standard deviation of the mean).