Massachusetts Institute of Technology: Srini Devadas and Eric Lehman's "Introduction to Probability"

Read Section 1.5 and Section 1.6 on pages 6 - 9. This reading discusses the third and fourth steps of the four-step process for building a probabilistic model for solving probability problems. In the third step, probabilities are assigned using the possibility tree drawn during steps one and two. In step three, probabilities are assigned to the edges of the tree. At each level of the tree, the branches of a node represent possible outcomes for that node. If the outcomes of a node are assigned the same probability (the outcomes of a node add to 1), we say that they represent equally likely outcomes.