Statistics - Moment Generating Functions

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SUMMARY

The moment generating function (MGF) for the random variable X is given as M[X(t)] = 1/(1+t). To find the third moment of X about the point x = 2, substitute n=3 and a=2 into the formula E[(X-a)^n]. Expand (X-a)^n to polynomial form and substitute into the expression to obtain the sum of moments about zero, which can then be calculated using the MGF.

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  • Understanding of moment generating functions (MGFs)
  • Familiarity with the concept of moments in probability
  • Knowledge of polynomial expansion techniques
  • Basic proficiency in statistical expectations and calculations
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  • Study the properties of moment generating functions (MGFs)
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little neutrino
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If the moment generating function for the random variable X is M[X(t)] = 1/(1+t), what is the third moment of X about the point x = 2? The general formula only states how to find moments about x = 0. Thanks!
 
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The n-th moment of X about a is defined as ##E[(X-a)^n]##.

Substitute n=3 and a=2 into that, then expand ##(X-a)^n## to polynomial form and substitute that into the above expression. You will get the sum of a bunch of moments about zero, which you can then use the MGF to calculate.
 
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andrewkirk said:
The n-th moment of X about a is defined as ##E[(X-a)^n]##.

Substitute n=3 and a=2 into that, then expand ##(X-a)^n## to polynomial form and substitute that into the above expression. You will get the sum of a bunch of moments about zero, which you can then use the MGF to calculate.

Ok I got it! Thanks so much! :)
 

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