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| | The '''geometric distribution''' is a discrete distribution which describes the | | The '''geometric distribution''' is a discrete distribution which describes the |
| − | number of repetitions of a [[Bernoulli experiment]] to get a success. Therefore | + | number of repetitions of a [[Bernoulli experiment]] to get a success. Therefore, |
| | its support are the positive integers, {1,2,3,…} | | its support are the positive integers, {1,2,3,…} |
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| | Some authors describe the geometric distribution as the number of repetitions | | Some authors describe the geometric distribution as the number of repetitions |
| | until the first success, its support being the non-negative integers | | until the first success, its support being the non-negative integers |
| − | {0,1,2,…}[[category:Probability and Statistics]] | + | {0,1,2,…} |
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| | == Mean and Variance == | | == Mean and Variance == |
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| | p</math><math>=\frac{p}{(1-q)^2}= \frac{1}{p}</math> | | p</math><math>=\frac{p}{(1-q)^2}= \frac{1}{p}</math> |
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| − | Similarly, the variance can be calculated:
| + | The variance can be calculated similarly: |
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| − | <math>Var(X) = \frac{1-p}{p^2}</math> | + | <math>Var(X) = \frac{1-p}{p^2}</math>. |
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| | + | == Probability-generating function == |
| | + | The [[probability-generating function]] <math>G_X(z) = \sum_{n=0}^\infty z^n \cdot \mathbf{P}[X=n]</math> is: |
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| | + | <math>G_X(z) = \frac{z\,p}{1-z(1-p)}</math>. |
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| | + | [[Category:Probability and Statistics]] |