본문 바로가기
Statistics

Moment generating function / property / Binomial / Exponential / Normal /Bernoulli /Geometric/ Gamma/ Poisson /Chi squared/

by jangpiano 2020. 7. 29.
반응형

Moment : core role in describing distributions. 


1. make a moment generating function --- Mx(t)

2. differentiate it 'r'th time ---M'r(t)

3. t=0 --- M'r(0) = E(X^r)

Moment Generating Function (MGF) :function that generates 'Moments'



<Moment generating function of Bernoulli distribution >



<Moment generating function of Binomial distribution>

 

<Moment generating function of Exponential distribution >


<Moment generating function of Standard Normal distribution> 


<Moment generating function of Geometric distribution >


<Moment generating function of Poisson distribution>


<Moment generating function of Gamma distribution>


 

<Moment generating function of Chi-squared distribution >


<Moment generating function of Uniform distribution >


<Moment generating function of Beta distribution >





Properties of Moment Generating Function (MGF)


       

 



'Uniqueness' means ' If X and Y has same moment generating function, X and Y have same distribution'


Joint Moment Generating Function 


Joint Moment Generating Function <Independent>


You can easily find Joint moment generating function of X and Y with multiplying moment generating function of X with Y when they are independent. 


Joint Moment Generating Function <dependent>


반응형