# Homework Help: Show how the variance decrease as degrees of freedom/sample size get bigger

1. Apr 10, 2012

### rogo0034

1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

I'm confused actually how to go about this. Sounds very simple, but when i do what they suggest, 'first, find the variance of (n-1)s22

i get larger variances rather than smaller, which makes no sense. should i be using the chart for this? (below)

2. Apr 10, 2012

### Ray Vickson

Since you don't tell us what the chart represents, it is impossible to tell if it is relevant or not; I suspect not.

You are told that $V = (n-1)S^2/\sigma^2$ has a Chi-squared distribution with (n-1) degrees of freedom. Do you know the variance formula for the Chi-squared distribution? (It is readily available.)

RGV

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