Ok, $\displaystyle \bar{R}^2=1-(1-R^2)\frac{n-1}{n-k}$

and $\displaystyle \bar{R}^2\leq R^2$

Given this equation:

$\displaystyle Ln[C]=4.30-1.34*Ln[P]+0.17*Ln[Y]$

The sample was 46 states.

$\displaystyle n=46, \ k=3, \ \bar{R}^2=0.27$

$\displaystyle R^2=\frac{(\bar{R}^2-1)(n-k)}{n-1}+1=\frac{(.27-1)(46-3)}{46-1}+1=0.302$

Is the correct derivation of $R^2\mbox{?}$