1. ## variance value

Hi;

I know the formula for variance and that a low value means the data is more compact
and a larger value means spread out more.

But what does the value actually relate to?

2. ## Re: variance value

Pretty much just what you said: how much the data "varies" or is spread out. Essentially, it tells us how "random" the data is.

3. ## Re: variance value

It is a measure of spread
for more details look here..:
Variance - Wikipedia, the free encyclopedia

4. ## Re: variance value

Variance,average distance to the mean squared so lets say I have a data set of

3,4,6,7 Therfore mean=5

variance=2.5. I get average distance as 2+1+1+2=6/4 1.5squared equals 2.25.

Why is this?

5. ## Re: variance value

The average of several numbers which have been squared is not equal to the average of the numbers then squared.

Suppose you have 2 numbers a and b
The average of their squares is $\frac{a^2+b^2}{2}$

The square of their average is $(\frac{a+b}{2})^2=\frac{a^2+2ab+b^2}{4}$

You can see that they are different values.