Example of a One-Tailed Test

Which of the following best describes when the null hypothesis is rejected in a one-tailed test?

If a researcher conducts a one-tailed test predicting that a new study technique will increase exam scores, but the results show a statistically significant decrease in scores, the researcher must fail to reject the null hypothesis.

A psychologist is conducting various studies using a one-tailed hypothesis test. Match each research scenario with the appropriate statistical decision and the rationale for that choice.

Arrange the following steps to reflect the logical process and the specific constraints involved when a researcher correctly applies a one-tailed hypothesis test in psychological research.

A psychologist predicts that a new mindfulness app will decrease stress levels and decides to use a one-tailed test. What is the primary statistical advantage of this decision compared to using a test that looks for a change in either direction?

A clinical researcher utilizes a one-tailed test ($\alpha = 0.05$) to evaluate the hypothesis that a new medication will decrease heart rate. If the medication unexpectedly causes a statistically extreme increase in heart rate, the researcher is forced to fail to reject the null hypothesis. From an evaluative standpoint, this demonstrates that the one-tailed test is inherently biased because it treats any result in the unpredicted direction as statistically _____ to a result showing no change.

A one-tailed test increases the likelihood of finding a statistically significant result in the predicted direction by utilizing a(n) _____ critical value.

A cognitive psychologist hypothesizes before data collection that a new memory training program will increase recall scores, and decides to use a one-tailed test. After compiling the data, the results show that participants in the training program actually had an extremely large, statistically significant decrease in recall scores. True or False: Under the rules of this one-tailed test, the psychologist can reject the null hypothesis because the result was highly extreme.

A researcher is planning a study to test whether a new focus app increases study time, using a one-tailed test. Match each research design component with its correct outcome or requirement based on the properties of a one-tailed test.

A developmental psychologist wants to evaluate and apply a one-tailed hypothesis test to determine if a new educational game increases spatial reasoning skills. Order the steps of this research evaluation process from the initial design phase to the final statistical decision.

Define a one-tailed test based on when the null hypothesis is rejected, and describe its primary advantage and disadvantage in statistical testing.

Based on the properties of the chosen statistical test, what must the researcher decide regarding the null hypothesis, and why? Explain this outcome in terms of the test's critical value.

A clinical researcher believes a new cognitive therapy will decrease intrusive thoughts in patients. The researcher wants to maximize the statistical chance of detecting this specific improvement if the therapy works. What specific type of hypothesis test should they apply before collecting data, and what structural feature of this test achieves their goal?