How to tell if a hypothesis test is left or right tailed

Step 1. Set up hypotheses and select the level of significance α. H 0: Null hypothesis (no change, no difference); H 1: Research hypothesis (investigator's belief); α =0.05.

Statistics Examples

For a left tailed test we need to check if the test statistic (TS) is smaller than the critical value (CV). If the test statistic is smaller the critical value, the test statistic is in the rejection region.

Do mathematic

Deal with math equations

Math equations can be difficult to deal with, but with practice, they can become easier.

Figure out mathematic problems

Get Support

If you're feeling overwhelmed or need some support, there are plenty of resources available to help you out.

Do homework

Get the Most useful Homework solution

Looking for the most useful homework solution? Check out our website for the best tips and tricks.

ask

Left Tailed Test or Right Tailed Test ? How to Decide

If your alternative is that the mean is not zero, then you do a two-tailed test. If your alternative is that the mean is greater than zero (or less than zero, either one) you do a one-tailed test. But