### Coefficient of Determination

Posted:

**17 Sep 2010, 17:57**Good Morning, I Have two main questions about r^2:

1. If I am doing a P300 experiment with two subjects, and I found that one has a bigger value of r^2 than the other one, what this exactly means? That one can evoked stronger the P300?

2. In the dissertation that is posted here to find more information about coefficient of determination, I found that the equation describes the correlation coefficient and no the coeficcient of determination, according to Wonnacott and Wonnacott (r^2=Sxy/SxSy). I know how you calculate this in the software but I would like to have more clarity of this concept, the latter because I tried to do it by myself and I don't know how to calculate the covariance (SxSy) between two vectors of different lenghts (at least this is no possible in Excel).

Thank you so much,

_________________

Eliana

1. If I am doing a P300 experiment with two subjects, and I found that one has a bigger value of r^2 than the other one, what this exactly means? That one can evoked stronger the P300?

2. In the dissertation that is posted here to find more information about coefficient of determination, I found that the equation describes the correlation coefficient and no the coeficcient of determination, according to Wonnacott and Wonnacott (r^2=Sxy/SxSy). I know how you calculate this in the software but I would like to have more clarity of this concept, the latter because I tried to do it by myself and I don't know how to calculate the covariance (SxSy) between two vectors of different lenghts (at least this is no possible in Excel).

Thank you so much,

_________________

Eliana