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Define a one-tailed test based on when the null hypothesis is rejected, and describe its primary advantage and disadvantage in statistical testing.
Question: Define a one-tailed test based on when the null hypothesis is rejected, and describe its primary advantage and disadvantage in statistical testing.
Sample answer: A one-tailed test is a hypothesis test in which the null hypothesis is rejected only if the test statistic is extreme in one specific direction, which must be hypothesized before data collection. Its primary advantage is that by utilizing only a single critical value, it increases the likelihood of finding a statistically significant result if the data trends in the expected direction. The primary disadvantage is that it completely eliminates the possibility of rejecting the null hypothesis if the results trend in the opposite direction.
Key points:
- The null hypothesis is rejected only if the test statistic is extreme in one specific direction.
- The specific direction must be hypothesized prior to data collection.
- It utilizes only a single critical value.
- Advantage: Increases the likelihood of finding a statistically significant result if data trends in the expected direction.
- Disadvantage: Completely eliminates the possibility of rejecting the null hypothesis if results go in the opposite direction.
Rubric: A full credit response must define the test as focusing on a single specific direction determined prior to data collection, mention the use of a single critical value, and correctly identify both the advantage (increased likelihood of finding significance in the expected direction) and disadvantage (inability to reject the null hypothesis in the opposite direction).
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Research Methods in Psychology - 4th American Edition @ KPU
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