# relationship between direction and one or two tail

Please help with the following abnormal psychology problem. Step by step discussions are provided.

When designing an experiment, the research hypothesis may be directional or non-directional.

1) Identify the differences between a directional and non-directional hypothesis.

2) Discuss how the directionality is related to the one- and two-tailed t-test.

3) Is there an assumption that is violated if a two-tailed t-test is used with a directional hypothesis? Please explain your reasoning.

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#### Solution Preview

For a directional hypothesis, it attempts to exercise a specific or one-tailed prediction concerning the expected result from the analysis. In this case, you can assume that when one independent variable is manipulated, you can not only predict that the population means will differ, but also predict which population will produce a relatively higher mean and which will produce a relatively lower ...

#### Solution Summary

The solution provides detailed explanation about the relationship between direction and two/one tailed test.