Continuous
Probability Distributions
Name |
Probability Density Function (pdf), f(x) |
Mean, Variance, Moment Generating Function |
Comments |
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Uniform over (a, b) |
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¥ ¥ non-informative, randomness distribution |
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Gamma parameters |
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¥ Very rich family with different shapes |
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Exponential parameters |
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¥ Gamma with n=1 ¥ (survival function) ¥ memoryless property |
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Chi-square parameter |
(nu) is called
the degrees of freedom |
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¥ Gamma with |
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Beta parameters |
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¥ A good model for proportions (Bayesian inference) |
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Normal parameters |
Standard Normal m=0,
s=1 |
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¥ Bell shaped curve ¥ To find a normal probability use the Table 2.3 on page
81 ¥ If has then has ¥ Normal
approximation to binomial. Let X has Binom(n,q). Make the continuity correction and use the fact that |
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Bivariate Normal |
Circular normal
distribution r=0, s1=s2 |
¥ If X and Y have a bivariate normal distribution then 1. Y given X=x has a normal distribution with 2. X given Y=y has a normal distribution with 3. X and Y are independent iff r=0. |
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