Which is the correct statistical test to use?

This paper explains how to select the correct statistical test for a research project, clinical trial, or other investigation. The first step is to decide in what scale of measurement your data are as this will affect your decision-nominal, ordinal, or interval. The next stage is to consider the purpose of the analysis-for example, are you comparing independent or paired groups? Several statistical tests are discussed with an explanation of when it is appropriate to use each one; relevant examples of each are provided. If an incorrect test is used, then invalid results and misleading conclusions may be drawn from the study.