Chapter 7

complement of event

The complement of event A consists of all outcomes that are NOT in A.

Addition Rule of Probability

P(A or B) = P(A) + P(B) - P(AB) *OR, EITHER*

Intersection of Events

The intersection of events is given by the outcomes that are common to two (or more) events.

Union of two events * OR*

The union of events A and B is the event containing all sample points that are in A or B or both Both A and B

relative frequency approach

expresses the probability of an outcome as the relative frequency of its occurrence based on past experience

Classical Approach

assigning equal probabilities to all the simple events

subjective approach

assigns probability to an event based on personal judgment

Three Approaches to Assigning Probabilities

classical, relative frequency, subjective

mutually exclusive events

events that cannot happen at the same time

intersection

the event that occurs when two or more other events occur

Joint Probability

the probability of the intersection of two events

Conditional Probability *GIVEN*

the probability that one event happens given that another event is already known to have happened

multiplication rule

the rule that allows us to calculate the probability of the intersection of two events;

Probability of an Event

the sum of the probabilities of the simple events that constitute the event.

event

a set of one or more simple events

three rules that enable us to calculate the probability of more complex events from the probability of simpler events

complement, multiplication rule, Addition Rule

marginal probabilities

computed by adding across rows or down columns, are so named because they are calculated in the margins of the table.