T-tests are used to compare means in which scenario?

T-tests are used to compare means in which scenario?

• A. Among three or more groups.
• B. Between two independent groups.
• C. Between two related groups or pretest/posttest.
• D. To examine relationships between variables.

Answer: (C)

T-tests are used to determine if two means differ, and they come in two main flavors depending on how the data are paired. When you have two related measurements on the same subjects—like a pretest and a posttest—the paired (related-samples) t-test is used. The analysis focuses on the difference between each pair, calculating the average difference and its variability, then testing whether that average difference is zero. This pairing removes much of the individual variability that could obscure the effect, giving the test more power to detect a real change. In contrast, comparing means from two independent groups would use the independent-samples t-test, which handles two separate groups without pairing. Scenarios with three or more groups call for ANOVA, and exploring relationships between variables points toward correlation or regression, not a t-test.

T-tests are used to determine if two means differ, and they come in two main flavors depending on how the data are paired. When you have two related measurements on the same subjects—like a pretest and a posttest—the paired (related-samples) t-test is used. The analysis focuses on the difference between each pair, calculating the average difference and its variability, then testing whether that average difference is zero. This pairing removes much of the individual variability that could obscure the effect, giving the test more power to detect a real change.

In contrast, comparing means from two independent groups would use the independent-samples t-test, which handles two separate groups without pairing. Scenarios with three or more groups call for ANOVA, and exploring relationships between variables points toward correlation or regression, not a t-test.