PSY 207 Lecture 8: Probability and Continuous Variables
Document Summary
Figuring out probabilities for most problems in the behavioral sciences is very difficult because: we deal with continuous variables rather than discrete events, we don"t kno(cid:449) the (cid:396)elati(cid:448)e f(cid:396)e(cid:395)uencies in the population of interest. This is a very hard problem because: we don"t ha(cid:448)e access to the enti(cid:396)e population and so (cid:449)e don"t kno(cid:449) the t(cid:396)ue f(cid:396)e(cid:395)uency of people taller than 6 feet, height is a continuous measure. The solution is to express probabilities in terms of proportion (area) beneath a frequency curve. For example- proportion of people in the population taller than 6 feet. Normal distribution: distributions of things we study are constructed based on a hypothetical distribution, the normal distribution. The shape of the normal distribution is described by an equation: also described by proportion of area in each section. The important characteristics are: it is symmetrical: 50% of the scores fall above & below mean, most of the scores pile up at the mode.
