How to Find a Critical Value for a Right-Tailed Test
Finding a critical value for a right-tailed test will have a familiar feel to it if you are used to looking up areas in a z-table (which should have been covered by this point in any elementary statistics class). This article shows you how to find α=.079 for a right-tailed test.
Step 1: Draw a diagram, like the one above. Shade in the area in the right tail.
This area represents α.
Step 2: Subtract alpha (α) from 0.5.
Step 3: Find the result from step 2 in the center part of the z-table.
The closest area to 0.4921 is 0.4922 at z=2.42.