Example 2

The variable Z is a standard normal random variable. What is the probability that z is greater than 1.2 or less than -1.2?

Figure 18

The desired area is to the right of 1.2 and to the left of -1.2. Since normal distributions are symmetrical, and the areas are the same, you can calculate the lower tail area and simply multiply by 2.

Table 12-24 Example converting from lower tail

Keys

Display

Description

 

 

 

J7Gy]F

 

store the value.

 

.115070

Calculate the lower tail area and

 

 

 

PG4

.230139

Calculates the result.

 

 

 

 

134 Statistical Calculations