Find the indicated area under the curve of the standard norm

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 1.9 and z =1.9 (or within 1.9 standard deviations of the mean).

(Round to two decimal places as needed.)

Find the indicated IQ score. The graph to the right depicts IQ scores of adults, and those scores are normally distributed with a mean of 100 and a standard deviation of 15.

A graph with a bell-shaped curve, divided into 2 regions by a line from top to bottom, on the left side. The region right of the line is shaded and labeled 0.97.

The indicated IQ score, x, is ____________   

Assume that adults have IQ scores that are normally distributed with a mean of 107 and a standard deviation of 15. Find the third quartile Upper Q3, which is the IQ score separating the top 25% from the others.

The third quartile, Upper Q3, is _________

Solution

The indicated IQ score, x, is 128.21.

The third quartile, Upper Q3, is 117.11