CJUS-K300 1nd Edition Lecture 6 Outline of Last Lecture I. VarianceII. Standard DeviationOutline of Current Lecture III. ProbabilityCurrent LectureThe way we refer to probability is P, the notation for the probability that event X will occur is P(X)Rules of ProbabilityBounding Rule – all probabilities are bounded between one and zero. 0 ≤ P(A) ≤ 1Complement Rule – If you know P(A) then you know P(Not A). P(Not A) = 1-P(A)Mutually exclusive events are when two events cannot occur at the same time. If A and B are mutually exclusive then P(A AND B) = 0 - Ex. In a deck of cards pulling a diamond and a heart are mutually exclusive. P(heart AND diamond) = 0 Addition Rule (either/or rule) for mutually exclusive events - A and B are mutually exclusive. P(A or B) = P(A) + P(B)- Ex. P(Hearts or Diamonds) = P(H) + P(D) o P(H) = .25o P(D) = .25o .25 + .25 = .5 or 5% probability Not all events are mutually exclusive. Addition Rule in general form: P(Hearts and Ace) ≠ 0P(A or B) = P(A) + P(B) – P(A and B) These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.You subtract P(A and B) in order to not double count the event and overesitmate the probability. If you do not subtract A and B you would be counting it twice because you have already included A and B separately. - Ex. P(Heart or Ace) = P(H): .25 + P(A): .08 – P(H & A): .02 = .31 or 31% - Explanation – Under the assumption that there are 52 cards in a decko P(Hearts) = 13/52 or . 25o P(Ace) = 4/52 or .08 o P (H & A) = 1/52 or
View Full Document
Unlocking...