We can use set notation to describe probabilities.

The sample space, usually denoted by S, of a random experiment is the set of all possible outcomes. Thus, each outcome is an element of the sample space,and each event, being a collection of some outcomes, is a subset of the sample space.

Thus P(E) = n(E)/n(S) where n(E) is the number of outcomes in the event E, and n(S) is the number of outcomes in the sample space S.

And we study the basic properties of probabilities: 0 <= P(E) <= 1, and P(E’) = 1 – P(E).

We further study how to use a possibility diagram or a tree diagram to represent a sample space to help us figure out the probability problem.

Homework:

P61, #24 – #29; P65, #3 – #8.