The program is run by former heroin addicts. A hypothesis is a set of beliefs about the nature of the world, it is usually a belief about a relationship between two or more variables. Sometimes a distinction is made between inductive and deductive methods of hypothesis testing. In the inductive method we observe events and then devise a hypothesis about the events observed. For example, might notice that Armaund, a retired man whom we know, likes to watch wrestling on television. In the jargon of hypothesis testing, we want to know which level of the independent variable will have a beneficial effect on the dependent variable. Piaget, a Swiss psychologist, called the highest level of cognitive development the formal stage of thought. Thus, It should be able to recognize that the same principles used in hypothesis testing were needed in this task and be able to apply them correctly in order to solve this seemingly unrelated problem.