Conditional moment generating functions

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SUMMARY

The discussion focuses on the calculation of expected values and variances for a random variable T conditioned on a uniform random variable U over the interval (0,2). The moment generating function (mgf) for T given U is defined as \(\frac{1}{1-ut}\). Key findings include that E(U) equals 1, and the conditional expectations E(T|U) and variances Var(T|U) can be derived using the mgf. The unconditional expectation and variance of T can be computed using the double expectation theorem, specifically E(T) = E(E(T|U)).

PREREQUISITES
  • Understanding of moment generating functions (mgf)
  • Knowledge of conditional expectations and variances
  • Familiarity with uniform distributions
  • Concept of double expectation theorem
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  • Study the properties of moment generating functions in detail
  • Learn about conditional distributions and their applications
  • Explore the double expectation theorem and its implications in probability
  • Investigate the relationship between mgf and moments of random variables
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Students and professionals in statistics, probability theory, and data analysis who are working with random variables and their distributions, particularly in the context of conditional expectations and moment generating functions.

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Homework Statement


Random variable U is continuous uniform in the time interval (0,2)
T|U (T given U) is modeled by the mgf [tex]\frac{1}{1-ut}[/tex]
Find:
a) E(U)
b) E(T|U) and Var(T|U)
c) E(T) and Var(T)


Homework Equations





The Attempt at a Solution


a) This one was fine, E(U)=1
b) I know E(X)=m'(0), but how does it work with conditional distributions?
c) Again, not sure how I find the marginal distribution of T from the conditional mgf.

Any pointers appreciated. :)
 
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How do you use any mgf to find the mean of the underlying variable? The same method applied to

[tex] \frac 1 {1-ut}[/tex]

will give E(T | U) (it will be a function of U), and you can also use the conditional mgf to find V(T | U) (another function of U). To find the unconditional expectation and Variance of T, use the notion of double expectation. (E(T) = E(E(T|U)))
 

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