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Statistics Ch.4
4.1 Basic Concepts of Probability
Term | Definition |
---|---|
event | any collection of results or outcomes of a procedure |
simple event | an outcome or an event that can't be further broken down into simpler components |
sample space (for a procedure) | consists of ALL possible simple events |
P denotes | a probability |
A, B, and C denotes | specific events |
P(A) denotes | the probability of event A occurring |
Probability Limits | Always express a probability as a fraction/decimal number btwn 0 and 1 - probability of an impossible event is 0 - probability of an event that's certain to occur is 1 - for any event A, probability of A is btwn 0 and 1 inclusive |
An event is Unlikely if | the probability is very small- 0.05 or less |
An event is Rare if | probability is less than 0.001 |
Law of Large Numbers | As a procedure is repeated again and again, the relative frequency probability of an event tends to approach the actual probability |
Subjective Probabilities | the probability of event A is estimated by using knowledge of the relevant circumstances |
Odds of an event occurring | the ratio of the number of ways the event can occur (successes) to the number of ways the event can't occur (failures) a:b |
odds against an event occurring | ratio of the number of the ways an event cant occur (failures) to the number of ways the event can occur (successes) b:a |
Payoff odds against event A occurring | ratio of net profit (if you win) to the amount bet (net profit) : (amount bet) |