Explain the difference between a one-tailed and two-tailed t-test using your own words. Validate your explanation by citing credible expert sources (textbooks, peer-reviewed journal articles, etc.).

State two research hypotheses that can be tested using a one-tailed t-test, and discuss why a one-tailed t-test would be appropriate for those hypotheses.

State two research hypotheses that can be tested using a two-tailed t-test, and discuss why a two-tailed t-test would be appropriate for those hypotheses.