Ninth Edition CoverGraziano & Raulin
Research Methods (9th edition)

Chapter 7 Exercises
Correlational and Differential
Methods of Research

The following exercises are designed to give you hands-on practice of the skills learned in this chapter.

  1. Briefly describe several research projects (e.g., Does Ritalin affect the growth of rats?). For each, identify appropriate comparison groups and potential confounding variables.

  2. Think of some examples of ethical considerations that would lead a researcher to use differential research rather than an experimental manipulation.

  3. How would you interpret the following correlations (statistical significance, "proportion of variance accounted for," and conceptual interpretations):
    (a) a .71 correlation (p=.002) between age and weight in laboratory mice
    (b) a -.32 correlation (p=.23) between anxiety scores and the number of correct answers on an arithmetic test for children
    (c) a correlation of .02 (p=.91) between the running speed of rats and the amount of illumination in a maze for rats

  4. Calculate and interpret the coefficient of determination for each of the following correlations: .06, .13, -.51, .62, -.17.