Sample spaces can also be described graphically with tree diagrams.
When a sample space can be constructed in several steps or stages, we can represent each of the n1 ways of completing the first step as a branch of a tree.
Each of the ways of completing the second step can be represented as n2 branches starting from the ends of the original branches, and so forth.
Figure 2-8 Venn diagrams.
2.1.4 Counting Techniques A printed circuit board has eight different locations in which a component can be placed. If four different components are to be placed on the board, how many different designs are possible?