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Key Concepts Study Tool: Chapter 11
Click on each concept below to check your understanding.
1. Equations used for z- and t-Tests with Two Samples
2. Calculating zobtained with Proportions
3.One-Tailed and Two-Tailed Tests
- Two-tailed tests measure the significance of a relationship, but not directionality.
- One-tailed tests measure the significance and direction of a relationship.
- The choice of test is theoretically driven. If you are trying to determine whether or not groups are equal, use a two-tailed test. If you believe that a group has more, or less, of a quality than another group, use a one-tailed test.
- To use a one-tailed test, a slight modification of the two-tailed test is needed, by using a different value from the z- or t- table.