● Random assignment: is where study participants are randomly assigned to a study group ● Factors: are the variables that experimenters control during an experiment in order to determine the population, for example a new drug for amnesia ● Response variable: is the result of the experiment where the explanatory variable is manipulated ● Subjects: The population on which the treatment is being applied ● Treatment: what is being tested

● retrospective expriments consist by simply observing the population

● prospective studies consist by applying a treatment on the population.