Researchers, Scientists, Engineers, Students, Politicians, Economists, Political Analysts, Financial Analysts, Statisticians, and most of us the practitioners use statistics to answer questions or to support decision making that require data analysis. Statistics help to describe the results of, among others, investigations, experiments, and observations. When data about the subject or object of interest is somehow comprehensive, data analysis using descriptive statistics may be what is needed.
Unfortunately, in the world of statistics, things may not be that straightforward. The population of interest may not be fully observable or accessible. Hence, the statistician will have to make inference or, in statistics terms, appeal to inferential statistics. Inferential statistics involve statistical tests. One of the major issues facing statisticians and researchers is to choose which test to use.