Stats: Type of Tests

This document will explain how to determine if the test is a left tail, right tail, or two-tail test.

The type of test is determined by the Alternative Hypothesis ( H₁ )

Left Tailed Test

H₁: parameter < value
Notice the inequality points to the left

Decision Rule: Reject H₀ if t.s. < c.v.

Right Tailed Test

H₁: parameter > value
Notice the inequality points to the right

Decision Rule: Reject H₀ if t.s. > c.v.

Two Tailed Test

H₁: parameter not equal value
Another way to write not equal is < or >
Notice the inequality points to both sides

Decision Rule: Reject H₀ if t.s. < c.v. (left) or t.s. > c.v. (right)

The decision rule can be summarized as follows:

Reject H₀ if the test statistic falls in the critical region

(Reject H₀ if the test statistic is more extreme than the critical value)