# How do you use a chi square table?

1. Oct 31, 2012

### Artusartos

For example, if the moment generating function is (1-2t)^(-6), then the degree of freedom r=3, right? The question is asking me to find P(X< 5.23)...I want to use the chi-square table, but I'm not sure how...

This is what the question states:

If $(1-2t)^{-6}$, t<1/2, is the mgf of the random variabel X, find $P(X< 5.23)$.

2. Oct 31, 2012

### Ray Vickson

Do you have access to a chi-squared table? If you do, just read the user's manual! The point is that sometimes there are different ways of tabulating the same function; some tables might tabulate the left tail, others the right tail, etc. You need to read the instructions that come with the table, or at least look at the table captions.

If you do not have access to a chi-squared table, you can always express the answer in terms of a definite integral and then evaluate it is some way. There are many possibilities for this, but first you need to have the integral written down.

RGV

Last edited: Oct 31, 2012
3. Oct 31, 2012