Distribution of Sum of F distributed rv?

In summary, the question asks about the distribution of the sum of n F distributed random variables and the sum of n non-central F distributed random variables. To obtain the joint distribution, one would need to specify x values for the integral of each CDF and use characteristic functions. Some helpful references for this topic include the Wolfram MathWorld website and the book "Multivariate Statistics: High-Dimensional and Large-Sample Approximations" by Yasunori Fujikoshi, Vladimir V. Ulyanov, and Randeep Singh.
  • #1
saaagar10
1
0
Dear Good people,
I needed a help,
  1. what will be the distribution of sum of n F distributed random variables?
  2. what will be the distribution of sum of n non-central F distributed random variables?
Great if u can suggest some references too!
Thanks in advance!
 
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  • #2
saaagar10 said:
Dear Good people,
I needed a help,
  1. what will be the distribution of sum of n F distributed random variables?
  2. what will be the distribution of sum of n non-central F distributed random variables?
Great if u can suggest some references too!
Thanks in advance!

Are you asking for the joint distribution of the CDFs of a set of F distributions?:

[tex] F_{m_i,n_i}=\frac{\chi_{m_i}^2/m_i}{\chi_{n_i}^2/n_i}[/tex].

For m and n degrees of freedom.

First you would need to specify some [tex] x_i[/tex] for the integral of each CDF and then use the characteristic functions to obtain the joint distribution function.

http://mathworld.wolfram.com/F-Distribution.html

This may also help:

http://books.google.com/books?id=vt...e&q=Multivariate Joint F distribution&f=false

see d) p 104
 
Last edited:

Related to Distribution of Sum of F distributed rv?

1. What is the F distribution and how is it used?

The F distribution is a probability distribution that is used to model the ratio of two independent, normally distributed random variables. It is commonly used in statistical tests, such as ANOVA, to compare variances between groups.

2. How is the sum of F distributed random variables calculated?

The sum of F distributed random variables can be calculated by adding the individual F variables together. If X and Y are two independent F distributed variables with degrees of freedom (df) 1 and 2, respectively, then the sum Z=X+Y will have an F distribution with df 1+2=3.

3. What is the mean and variance of the sum of F distributed random variables?

The mean of the sum of F distributed random variables is equal to the sum of the individual means, while the variance is equal to the sum of the individual variances. In other words, if X and Y are two independent F distributed variables with means μ1 and μ2 and variances σ1^2 and σ2^2, respectively, then the sum Z=X+Y will have a mean of μ1+μ2 and a variance of σ1^2+σ2^2.

4. Can the sum of F distributed random variables be used to approximate other distributions?

Yes, the sum of F distributed random variables can be used to approximate other distributions, such as the Chi-Squared distribution. This is known as the F approximation to the Chi-Squared distribution, and it is used in many statistical tests, including the F-test and the ANOVA test.

5. What are some real-world applications of the distribution of sum of F distributed random variables?

The distribution of sum of F distributed random variables has many real-world applications in fields such as economics, engineering, and medicine. For example, it can be used in analyzing financial data, testing the effectiveness of new medical treatments, and studying the effects of different factors on product quality in manufacturing processes.

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