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524 bytes added ,  03:22, November 25, 2012
add kolmogorov probability
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For example, the probability of a tossed fair coin coming up heads is &frac12; = 0.5 = 50% because there is one favorable outcome (heads) out of 2 possible outcomes (heads and tails). Another common example is standard deck of 52 playing cards: there are 13 cards in each suit: spades, hearts, clubs and diamonds. After the deck is shuffled thoroughly, the probability that the top card on the deck is a heart is  <math>13 / 52 = 1 / 4 = 0.20</math>, or 20%.
 
For example, the probability of a tossed fair coin coming up heads is &frac12; = 0.5 = 50% because there is one favorable outcome (heads) out of 2 possible outcomes (heads and tails). Another common example is standard deck of 52 playing cards: there are 13 cards in each suit: spades, hearts, clubs and diamonds. After the deck is shuffled thoroughly, the probability that the top card on the deck is a heart is  <math>13 / 52 = 1 / 4 = 0.20</math>, or 20%.
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==Formal definition of probability==
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Let <math>S</math> be the sample space and <math>E</math> be a [[σ-algebra]] of events.  A probability function <math>P\colon E \to \mathbb{R}</math> is a function satisfying the Kolmogorov axioms of probability:
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#<math>P(A) \geq 0</math> for all events <math>A \in E</math>
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#<math>P(S) = 1</math>
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#If <math>\{A_n\}</math> is a countably infinite pairwise disjoint family of events in <math>E</math>, then
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<math>P\left(\bigcup_{n=1}^\infty A_n\right) = \sum_{n=1}^\infty P(A_n)</math>
    
==Empirical vs Theoretical Probability==
 
==Empirical vs Theoretical Probability==
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