Question

What is the probability of selecting a z score between -0.85 and 1.15?

A. 0.8749
B . 2.0
C . 0.6772
D . 0.1977

Answer 1

Correct choice is C

Explanation:

For the normal distribution (
`Z\sim N(0,1)`) the probability that a z score is between -0.85 and 1.15 is

`Pr(-0.85<z<1.15)=Pr(z<1.15)-Pr(z<-0.85).`

According to the normal distribution table:

`Pr(z<1.15)=0.8749,\\ \\Pr(z<-0.85)=1-Pr(z>0.85)=1-0.8023=0.1977,`

then

`Pr(-0.85<z<1.15)=Pr(z<1.15)-Pr(z<-0.85)=0.8749-0.1977=0.6772.`