Question

Determine the following z-scores: a. z0.1 = __________ b. z0.025 = __________

I don't understand the answer which has been posted. Thanks.

Answer 1

Solution:

We have to find z scores for following :

Part a) z_0.1

That is find z such that:

P( Z < z) = 0.1000

Look in z table for Area = 0.1000 or its closest area and find z value.

Area 0.1003 is closest to 0.1000 and it corresponds to -1.2 and 0.08

Thus z = -1.28

That is:

z_0.1 = -1.28

( If 0.1 area is in right tail then z_0.1 = 1.28 )

Part b) z_0.025

Look in z table for area = 0.0250 or its closest area and find z value

Area 0.0250 corresponds to -1.9 and 0.06

thus z critical value = -1.96

That is:

z_0.025 = -1.96

( if it is right tail area = z_0.025 = 1.96 )