Probability= sum of n uniformly distributed r.v.'s

In summary, the question is asking for the expected value of adding multiple uniform distributions with a range of 80 to 120. The suggested method is to use the linearity of the expected value operator, but the changing distribution may cause confusion. The Irwin-Hall distribution is another option to consider.
  • #1
Roni1985
201
0

Homework Statement


Xi ~ U(80,120)
find the E[X1+X2+...+Xn]=?

Homework Equations





The Attempt at a Solution



Why can't I do this?:
E[X1+X2+...+Xn]=n*E[X1]
and just find the expected value?

Is that because the distribution changes as we increase the number of elements of uniforms we sum?
Is there some trick here?

I found something called "Irwin–Hall distribution"... is this it?
 
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  • #2
You can do that. The expected value operator is linear.
 
  • #3
LCKurtz said:
You can do that. The expected value operator is linear.

I see, I guess the fact that the distribution changes, confused me...

Thanks.
 

1. What is the concept of "Probability = sum of n uniformly distributed r.v.'s"?

The concept of "Probability = sum of n uniformly distributed r.v.'s" refers to the idea that the total probability of an event occurring is equal to the sum of the probabilities of each individual outcome within that event. This is often used in probability and statistics to calculate the likelihood of a certain outcome when multiple variables are involved.

2. How do you calculate the sum of n uniformly distributed random variables?

To calculate the sum of n uniformly distributed random variables, you would first need to define the probability distribution of each variable. Then, you would use the formula for calculating the sum of independent random variables, which is the sum of their expected values. In the case of uniformly distributed variables, the expected value is equal to the average of the minimum and maximum values of the distribution.

3. Can the sum of n uniformly distributed random variables be greater than 1?

Yes, the sum of n uniformly distributed random variables can be greater than 1. This is because the sum of probabilities can exceed 1 when the events are not mutually exclusive. In other words, there can be some overlap or intersection between the different outcomes being considered.

4. How is the concept of "Probability = sum of n uniformly distributed r.v.'s" applied in real-life situations?

The concept of "Probability = sum of n uniformly distributed r.v.'s" is commonly applied in various fields such as finance, engineering, and social sciences. For example, it can be used to calculate the risk of a certain investment portfolio, predict the likelihood of an earthquake occurring in a certain area, or estimate the probability of a certain demographic group voting for a particular candidate in an election.

5. Are there any limitations to using "Probability = sum of n uniformly distributed r.v.'s" in calculations?

While the concept of "Probability = sum of n uniformly distributed r.v.'s" is widely applicable, there are some limitations to its use. One limitation is that it assumes that the variables are independent, meaning that the outcome of one does not affect the outcome of the others. It also assumes that the variables are distributed uniformly, which may not always be the case in real-life situations. Additionally, this concept may not be appropriate for more complex or non-linear relationships between variables.

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