Final answer:
Contrast tests are used for planned comparison, and they allow researchers to methodically analyze and evaluate differences between group means in fields such as medicine, politics, and education.
Step-by-step explanation:
Contrast tests are used for planned comparison. These tests are a statistical tool employed to compare different group means under certain assumptions, analyzing the differences to determine if they are statistically significant. One common application of contrast tests is to compare and evaluate two or more groups in various settings, such as in medical, political, or educational research.
For instance, in medicine, clinicians might use contrast tests to compare and contrast the effectiveness of differing treatment methods. If researchers wished to evaluate the impact of different diet and exercise programs, or if they looked to understand the effectiveness of SAT or GRE preparatory courses, contrast tests would allow them to conduct these analyses methodically.
In reference to the options provided:
- a. Beta Comparison refers to a statistical power analysis that is not directly related to contrast testing.
- b. Planned Comparison, which is the correct answer, involves comparisons that are hypothesized before data is collected.
- c. Pairwise Comparison usually refers to comparing each pair of groups, which can be done using contrast tests but is not the primary purpose they serve.
- d. Post-Hoc Comparison are those comparisons that are not specified before the study and are usually performed after an ANOVA when no prior hypothesis was stated.