What determines the decision of whether to use a one-tailed test or a two-tailed test when testing hypotheses to make inferences about a population mean?
A) the sample size and the estimated standard error
B) the nature of the situation and what the researcher is trying to demonstrate
C) the level of significance of the test
D) the sample size relative to the population size
E) the standard error relative to the sample variance

Question

What determines the decision of whether to use a one-tailed test or a two-tailed test when testing hypotheses to make inferences about a population mean?
A)	the sample size and the estimated standard error
B)	the nature of the situation and what the researcher is trying to demonstrate
C)	the level of significance of the test
D)	the sample size relative to the population size
E)	the standard error relative to the sample variance

Quizplus · Accepted Answer

The decision of whether to use a one-tailed test or a two-tailed test depends on the nature of the situation and what the researcher is trying to demonstrate. A one-tailed test is used when the researcher has a specific hypothesis about the direction of the effect (i.e., an increase or decrease in the population mean) and wants to test whether the data supports this hypothesis. A two-tailed test is used when the researcher does not have a specific hypothesis about the direction of the effect and wants to test whether the data supports a difference in either direction from the null hypothesis. Therefore, the decision to use a one-tailed or two-tailed test should be based on the research question and the nature of the hypothesis being tested, rather than statistical criteria such as sample size or level of significance.

What Determines the Decision of Whether to Use a One-Tailed