Z is a standard normal random variable. The P(-1.96 Z -1.4) equals
A)0.8942
B)0.0558
C)0.475
D)0.4192

Question

Z is a standard normal random variable. The P(-1.96  Z  -1.4) equals
A)0.8942 
B)0.0558 
C)0.475 
D)0.4192

Quizplus · Accepted Answer

Using standard normal distribution tables or a calculator, we find that P(-1.96 < Z < -1.4) = 0.0808 and P(Z > 1.96) = 0.025. Therefore, the desired probability is the sum of these two probabilities, which is 0.0808 + 0.025 = 0.1058. However, since we are looking for P(-1.96 < Z < -1.4) and not P(Z < -1.4), we need to subtract the area to the left of -1.96 from 0.0808, which is 0.025. Therefore, the answer is P(-1.96 < Z < -1.4) = 0.0808 - 0.025 = 0.0558, which corresponds to choice B.

Z Is a Standard Normal Random Variable