# R square

1. May 1, 2006

### prof.DK

Hi there,

I have googled for the R square formula, but it's very confusing, so I need some help. Please come up with an example on how to use it, if I have a exponential function on how i want to calculate its R square.

Thanks

2. May 1, 2006

### Integral

Staff Emeritus
$R^2$ is used to gauge the "goodness" of "fit" of a data set to some known function. So you need a data set and a function, you cannot meaningfully speak of [tex]R^2[/itex] of a function by itself.

3. May 2, 2006

### prof.DK

If I then have a table of data:

0 2
40 6
80 8
120 12
160 18
200 24
240 42
280 82
320 110
360 190
400 300
440 500
480 800

... and I want to find the R^2, what should I do (I don't want to use software)?
:surprised

4. May 2, 2006

### J77

Last edited: May 2, 2006
5. Mar 25, 2010

### neptune7678

google: "Pearson product moment correlation coefficient"

multiply PPMCC by itself for R^2

http://mathbits.com/Mathbits/TISection/Statistics2/correlation.htm [Broken]

sorry it's 4 years late...

Last edited by a moderator: May 4, 2017