Question

Find the probabilities for a standard normal random variable Z.

a.P(Z>2.5)

b.P(1.2

Answer 1

Explanation:

find the attachment showing std normal curve symmetrical about y axis.

Equal probabilities on either side of the mean thus the total probability to the right of mean is 0.50

From the table we can find that

a) P(Z>2.5) = 0.5- area lying between 0 and 2.5

= 0.5-0.4938 =0.0062

b) P(1.2<z<2.2) = F(2.2)-F(1.2)

= 0.9861-0.3849

=0.6012