lecture 1 - probability I

Basic concepts and conditional probability

Example：

ìThat is, theprobability that the outcome is not in A is 1 minus the probability that it isin A. The complement of the sample space S is the null event ∅, which contains no outcomes. Therefore: P(∅) = 0.

ìFor any eventsA and B we define A ∪ B, called the union of A and B, as the event consisting of all outcomesthat are in A, or in B, or in both A and B. Also, we define their intersectionAB (sometimes written A ∩ B) as the event consisting of all outcomes that areboth in A and B.