In the previous two units we have discussed the purpose of research, the research report, subject selection, and the various types of research design. The final unit, including this chapter, will begin to add quantitative knowledge to your research repertoire, which will allow you to critically analyze not only the methodologies of research but also the statistical results. Before analyzing any data, however, and even before testing any subjects, the issues of variable selection and control, reliability, and validity must be addressed.
The purpose of any research is to determine if a theory is supported or not based on statistical analysis. A theory is an educated guess about a relationship but in order for research to be conducted on a theory, it must first be operationalized. To operationalize a theory, all variables must be defined and the methods of conducting the research must be determined. Once this is done, the resulting statement about the relationship is called a hypothesis. The hypothesis is what gets tested in any research study.