Finding Critical Values

Let us say that we can not find our Common Critical Value Table. What do we do?

90% Confidence Level

Step 1: Identify

= 100% - Confidence Level, 10%

= .10

Step 2: Identify one tail (Right)

/ 2 = .10 / 2

= .05 for the right tail

Step 3: Identify the cumulative area for the right tail, excluding the left tail.

= 1 - .05

= 1.645 Z- score

Now Identify the following critical values: za/2

• • • 99%
    • 99.5%
    • 98%
    • 84%
    • 81%