How do i calculate expectation of expectation?

  • Thread starter AndreTheGiant
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In summary, the formula for calculating expectation of expectation is E[E(X)] = E(X), and it differs from regular expectation in that it takes the average of all possible expected values rather than outcomes. Expectation of expectation can be negative if the random variable has a skewed distribution, and it represents the average expected value of a random variable. However, it cannot be used to make predictions and is only a theoretical concept.
  • #1
AndreTheGiant
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When i have stuff like

E(E(X)) or E(E(XY|X)) etc how do i evaluate a double expectation?

and for random vectors stuff like

E(E(X)'Y) or E(X'E(Y)) etc.
 
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  • #2
Not too sure about the vector examples, but for the first couple: Always deal with each expectation in turn. For example if E(X) = 4, E(E(x)) = E(4) = 4. The rules of expections should prove very useful as well, like taking constants outside the expectation sign.
 

1. What is the formula for calculating expectation of expectation?

The formula for calculating expectation of expectation is E[E(X)] = E(X). This means that the expected value of the expected value of a random variable is equal to the expected value of the random variable itself.

2. How is expectation of expectation different from regular expectation?

Expectation of expectation is the expected value of the expected value of a random variable, while regular expectation is the expected value of the random variable itself. Essentially, expectation of expectation is taking the average of all possible expected values, while regular expectation is taking the average of all possible outcomes.

3. Can expectation of expectation be negative?

Yes, expectation of expectation can be negative. This can occur if the random variable has a skewed distribution with a long tail on the negative side. In this case, even though the expected value of the random variable may be positive, the expected value of the expected value may be negative.

4. How do I interpret the expectation of expectation?

The expectation of expectation can be interpreted as the average expected value of a random variable. It tells us the central tendency of the expected values of a random variable. In other words, if we were to repeatedly sample from this random variable, the expectation of expectation would be the average of all the expected values we would calculate.

5. Can expectation of expectation be used to make predictions?

No, expectation of expectation cannot be used to make predictions. It is a theoretical concept that helps us understand the behavior of random variables. It does not provide information about specific outcomes or predictions about future events.

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