After reading this chapter, you should be able to:

4.1 Identify the types of variables involved in an explanation for a phenomenon.

4.2 Explain the characteristics of good hypotheses.

4.3 Discuss the role of defining concepts in research studies.

4.4 Discuss the validity and reliability of measures and ways to demonstrate them.

4.5 Discuss measurement precision and levels of measurement.

4.6 Distinguish between categorical and quantitative measures.