# Chi square problem

1. Sep 25, 2008

### dim&dimmer

1. The problem statement, all variables and given/known data
$$W = \frac{vS^2}{\sigma^2}$$, distributed as $$X^2_v$$
Find $$E(s^2) and Var(s^2)$$

2. Relevant equations
$$E(W) = v , Var(w)=2v$$

3. The attempt at a solution
Have been trying to figure this out with no luck. Can I use MLE for variance to show $$Var(s^2)= \sigma^2$$? Really don't know how to get started on this, any pointers would be appreciated.
DIM

2. Sep 25, 2008

Remember that for any random variable $$X$$ and constant $$k$$

$$E(kX) = kE(X), \quad Var(kX) = k^2 Var(X)$$

3. Sep 25, 2008

### dim&dimmer

Thank you,
Sheesh, should have posted my question .....days ago, pretty simple really.
Dimmer.