ABSTRACT
This chapter discusses the elements of research methods that affect the selection of appropriate statistical procedures. For the human performance professional, statistical analyses and research studies play a useful and important role in everyday life. To select efficient statistical procedures, some knowledge of research methods is required, and to select the best research design, knowledge of statistics is necessary. The essence of the scientific method is to gather information objectively and make decisions based on evidence. These decisions are based on probability, so there is room for error. Issues related to the validity of the overall experiment are important. Experimental validity issues are broadly classified as internal or external. Deciding which variables should be included in the analysis and how they should be included is the domain of experimental design. Proper experimental design is essential to correct interpretation of study results.
