Missing 'x' in Expectation Value Formula

In summary, the "x" in the Expectation Value Formula represents the random variable or quantity of interest, and it can be any measurable quantity. The "x" may be missing if it is implied or understood, and it can be solved for by plugging in information about other values in the formula. The "x" can be a negative value, but it is important to use appropriate values and probabilities. The Expectation Value Formula is essentially the same as finding the mean or average, but it is commonly used in the context of probability and statistics.
  • #1
Void123
141
0

Homework Statement



In my textbook, the formula for the expectation value is written as:

[tex] <x> = \int \Psi^{*}\Psi dx [/tex]

Shouldn't there be an [tex] x [/tex] next to [tex]|\Psi|^{2}[/tex] ?

Thanks.



Homework Equations





The Attempt at a Solution

 
Physics news on Phys.org
  • #2
yes it should read[tex]<x>=<\psi|x|\psi> = \int_{-\infty}^{\infty}\psi^*x\psi dx[/tex]

make sure you write it in this form too. Otherwise when you start putting in other operators like p you will get it wrong.
 

1. What is the "x" in the Expectation Value Formula?

The "x" in the Expectation Value Formula represents the random variable or the quantity we are interested in finding the average value of. It can be any measurable quantity, such as the outcome of a coin toss or the height of a person.

2. Why is the "x" sometimes missing in the Expectation Value Formula?

The "x" may be missing in the Expectation Value Formula if it is implied or understood based on the context of the problem. In some cases, the formula may be simplified if the random variable is not explicitly stated, and the "x" is assumed to be present.

3. How do I solve for the missing "x" in the Expectation Value Formula?

To solve for the missing "x" in the Expectation Value Formula, you will need to have information about the other values in the formula, such as the probability of each outcome and the corresponding values of the random variable. Once you have this information, you can plug it into the formula and solve for "x".

4. Can the "x" in the Expectation Value Formula be a negative value?

Yes, the "x" in the Expectation Value Formula can be a negative value. The random variable can take on any value, positive or negative, and the formula will still be valid. However, it is important to make sure that the values and probabilities used in the formula are appropriate for the context of the problem.

5. Is the Expectation Value Formula the same as the mean or average?

Yes, the Expectation Value Formula is essentially the same as finding the mean or average. It is a mathematical tool used to find the average value of a random variable based on its probability distribution. However, the term "expectation value" is commonly used in the context of probability and statistics.

Similar threads

  • Advanced Physics Homework Help
Replies
10
Views
978
  • Advanced Physics Homework Help
Replies
2
Views
860
  • Advanced Physics Homework Help
Replies
30
Views
1K
  • Advanced Physics Homework Help
Replies
1
Views
312
  • Advanced Physics Homework Help
Replies
9
Views
1K
Replies
14
Views
1K
  • Advanced Physics Homework Help
Replies
10
Views
580
  • Advanced Physics Homework Help
Replies
3
Views
1K
  • Advanced Physics Homework Help
Replies
8
Views
3K
  • Advanced Physics Homework Help
Replies
4
Views
4K
Back
Top