Tests of Hypotheses
One of the purposes of statistics is to enable us to make informed decisions based on some set of data. We will look here at a particular decision making process called hypothesis testing, an area of inferential statistics (in which we are trying to ‘infer’ something from the data). This aspect of statistics is often misunderstood, not only by students (Sotos, Vanhoof, Van den Noortgate and Onghena 2009) but also by scientists or other professionals who use statistical inference as part of their everyday work though are non-specialists in this area. The aim of this chapter is to introduce the ideas that lie behind hypothesis testing and to dispel the many misconceptions that arise commonly. We will keep this fi rst section fairly non-technical for the basic ideas behind hypothesis testing to be absorbed. It is important to have the opportunity to see the ‘big picture’ before being concerned with the minutiae.