Question

Find the indicated critical z value. Find zα/2 for α = 0.08

Answer 1

Refer to the diagram shown below.
The value of z that yields the expected central area takes into account the excluded areas at both tails.

Half the tail area is α/2 = 0.08/2 = 0.04.
The central area is 1 - 0.04 - 0.04 = 0.92.

From standard normal tables, obtain
z(α/2) = 1.75

Answer: 1.75