Probability: Difference between revisions

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===Chi-Sq Distribution===
===Chi-Sq Distribution===
* The ratio of two normalized Chi-sq is an F-distributions
* The ratio of two normalized Chi-sq is an F-distributions
** If <math>X \sim \chi^2_{d1}</math> and <math>Y \sim \chi^2_{d2}</math> then <math>\frac{X/d1}{Y/d2} \sim F(d1,d2)</math>
* If <math>Z_1,...,Z_k \sim N(0,1)</math> then <math>Z_1^2 + ... + Z_k^2 \sim \Chi^2(k)</math>
* If <math>Z_1,...,Z_k \sim N(0,1)</math> then <math>Z_1^2 + ... + Z_k^2 \sim \Chi^2(k)</math>
* If <math>X_i \sim \Chi^2(k_i)</math> then <math>X_1 + ... + X_n \sim \Chi^2(k_1 +...+ k_n)</math>
* If <math>X_i \sim \Chi^2(k_i)</math> then <math>X_1 + ... + X_n \sim \Chi^2(k_1 +...+ k_n)</math>