Joint, Marginal, and Conditional Probability

Abstract

This chapter introduces additional terms and concepts used in the study of probability, including Venn diagrams, independent events, and dependent events. The chapter focuses on two characteristics observed at the same time. In the example given in the chapter, the characteristics are eye dominance (i.e., left eye dominance or right eye dominance) and the presence or absence of “Morton’s toe” (Morton’s toe is a large second metatarsal which is longer than that the first metatarsal, or big toe; less than 20% of the human population has this condition). The chapter then analyses the distribution of these characteristics, both separately and simultaneously. In doing so, the chapter introduce the important concepts of joint probability, marginal probability, and conditional probability.