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Probability – the chance that an uncertain event will occur (always between 0 and 1)

Impossible Event – an event that has no chance of occurring (probability = 0)

Certain Event – an event that is sure to occur (probability = 1)

Assessing Probability probability of occurrence= probability of occurrence based on a combination of an individual’s past experience, personal opinion, and analysis of a particular situation

Simple event
An event described by a single characteristic
Joint event
An event described by two or more characteristics
Complement of an event A , All events that are not part of event A
The Sample Space is the collection of all possible events
Simple Probability refers to the probability of a simple event.

Joint Probability refers to the probability of an occurrence of two or more events. ex. P(Jan. and Wed.)

Mutually exclusive events is the Events that cannot occur simultaneously

Example: Randomly choosing a day from 2010
A = day in January; B = day in February
Events A and B are mutually exclusive

Collectively exhaustive events
One of the events must occur the set of events covers the entire sample space

Computing Joint and Marginal Probabilities
The probability of a joint event, A and B:

Computing a marginal (or simple) probability:

Probability is the numerical measure of the likelihood that an event will occur
The probability of any event must be between 0 and 1, inclusively

The sum of the probabilities of all mutually exclusive and collectively exhaustive events is 1

General Addition Rule
P(A or B) = P(A) + P(B) - P(A and B)
If A and B are mutually exclusive, then
P(A and B) = 0, so the rule can be simplified:
P(A or B) = P(A) + P(B)
For mutually exclusive events A and B

Computing Conditional Probabilities
A conditional…...

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