1 Find the indicated area under the curve of the standard no

1

Find the indicated area under the curve of the standard normal distribution, then convert it to a percentage and fill in the blank.

About _____% of the area is between z=?2.2 and z=2.2 (or within 2.2 standard deviations of the mean).

About?____% of the area is between z=?2.2 and z=2.2 (or within 2.2 standard deviations of the mean).

(Round to two decimal places as needed.)?

Solution

P(-2.2 < Z < 2.2)

= P(Z<2.2) - P(Z<-2.2)

= 0.9861 - 0.0139

= 0.9722

Hence approximately 97.22% of the graph area lies between these two points

Source: http://www.stat.ufl.edu/~athienit/Tables/Ztable.pdf (Z table values)