After completing this chapter you should be able to:
- Describe the purpose of the correlation coefficient.
- Differentiate between continuous and discrete variables and explain when discrete variables are dichotomous.
- Describe what is meant by the "third variable problem."
- Explain why the Pearson r measure is called the "product-moment correlation."
- Discuss when one would use a rank-order correlation coefficient.
- Explain why the Spearman rho is classified as a product-moment r.
- Describe the purpose of the point-biserial r.
- Explain how dummy coding is used to quantify dichotomous variables.
- Describe the relationship between the phi coefficient and the Pearson r.
- Discuss how one can show that Spearman rho, the point-biserial r, and the phi coefficient are simply cases of the Pearson r.
