This preview shows pages 1–4. Sign up to view the full content.
This preview has intentionally blurred sections. Sign up to view the full version.
View Full DocumentThis preview has intentionally blurred sections. Sign up to view the full version.
View Full Document
Unformatted text preview: 6.3 Probability Rules and Trees Complement Rule P(A) + P(A c ) = 1 P(A) = 1 P(A c ) Addition Rule: P(A B) = P(A) + P(B) P(A B) If A and B are mutually exclusive, then P(A B) = 0. So P(A B) = P(A) + P(B) for two mutually exclusive events. Conditional Probability: Multiplication Rule: P(A B) = P(A)*P(BA) = P(B)*P(AB) If A and B are independent events, then P(A B) = P(A)*P(B) ) ( ) ( )  ( B P B A P B A P = Example 6.5 page 171 A graduate statistics course has seven male and three female students. The professor wants to select two students at random to help her conduct a research project. What is the probability that the two students chosen are female? Let A represent the event that the first student chosen is female and B represent the event that the second student chosen is also female. The problem is that event B depends on what happens with event A. We are looking for P(A and B). We have: P(A) = 3/10 P(BA) = 2/9 We can use the multiplication rule P(A and B) = P(BA)P(A) P(A and B) = 3/10 * 2/9 = .067 Example 6.6 page 172 Suppose the professor is sick and will be out for two classes....
View
Full
Document
 Spring '08
 CathyDavis
 Statistics, Addition, Mutually Exclusive, Probability

Click to edit the document details