## Thursday, 16 January 2014

### Probability summary

Probability:
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Probability: How likely an event can occur

Probability =   The number of ways of achieving desired outcome
Total number of possible outcomes

Event will definitely occur = 1

Event will never occur = 0

Event will not occur = 1 - probability of event occurring
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Sample space: All the possible outcomes of an experiment

S = {a, b, c ...}

Sample point = 1 of the possible outcomes
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Mutually exclusive: Both events cannot occur at the same time

Probability (A or B) = P(A) + P(B)

Independent events: Both events can occur at the same time; Outcome does not affect probability of outcome of other event

Probability (A and B) = P(A) x P(B)
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Diagrams:

Probability diagrams:

Used for two independent events

Tree diagram:

Used for two or more events