Could anyone explain to me that why:let u=E[X]. then

  • Thread starter rukawakaede
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This means that if 'u' is defined to be the expected value of 'X', then its expectation value is also E[X]. This is true in general, as long as X is defined a.e. and the definition of expectation is consistent. So, in summary, the expected value of 'u' is always equal to the expected value of 'X'.
  • #1
rukawakaede
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could anyone explain to me that why:

let u=E[X]. then E=E[X]?

I am a bit confused. Thanks.
 
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  • #2


'u' is defined to be E[X]. It always going to be E[X]. Thus its expectation value is E[X].
 
  • #3


In general, if X=a a.e., then E[X]=a. If you want me to prove this, then you first need to tell me how you defined expectation, since the definition tends to vary...
 
  • #4


rukawakaede said:
could anyone explain to me that why:

let u=E[X]. then E=E[X]?

I am a bit confused. Thanks.


If a random variable is constant, then its average is that constant.
 
  • #5


Of course, I would be happy to explain this to you. Let's start by defining the terms in this equation. The variable u represents the expected value of a random variable X. This means that u is the average value that we would expect to see if we were to repeat an experiment involving X many times. The notation E[X] represents the expected value of the random variable X.

Now, to answer your question, the reason why E is equal to E[X] is because the expected value operator is a linear operator. This means that it follows the properties of linearity, such as the distributive property and the property of addition. In this case, since u is a constant (the expected value of X), we can treat it as a number and use the property of addition to show that E is equal to E[X].

In simpler terms, the expected value of a constant is always equal to the constant itself. So, in this case, E is equal to u, which is equal to E[X]. I hope this explanation helps to clarify any confusion you may have had. Please let me know if you have any further questions.
 

1. What does the equation "let u=E[X]" mean?

The equation "let u=E[X]" is a way of assigning a variable, in this case u, to represent the expected value of a random variable X. This means that u is a numerical value that represents the average outcome of X over many trials.

2. How is the expected value of a random variable determined?

The expected value of a random variable is determined by multiplying each possible outcome of the variable by its probability and then summing up these values. This calculation gives the average value that can be expected from the random variable.

3. Why is it useful to define a variable for the expected value?

Defining a variable for the expected value allows for easier understanding and manipulation of the equation. It also allows for the use of the variable in other equations or calculations involving the expected value.

4. Can you provide an example of using the equation "let u=E[X]"?

Sure! Let's say we have a random variable X representing the number of heads when flipping a fair coin twice. The possible outcomes for X are 0, 1, or 2. We can calculate the expected value of X by multiplying each outcome by its probability (0.25, 0.5, and 0.25 respectively) and then summing up these values. This gives us an expected value of 1, which we can then represent as u in the equation "let u=E[X]".

5. Is there a relationship between expected value and actual outcomes?

Yes, the expected value is a theoretical value that represents the average outcome over many trials. This means that in the long run, the actual outcomes should tend towards the expected value. However, in individual trials, the actual outcome may differ from the expected value.

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