Let us try to calculate the correlation coefficient for the fit of the leaf length for tree A. We just need to follow Equation (7.9):

octave:21> denom = (length(yA) - 1)*var(yA);octave:22> rcor = 1 – sA.normr^2/denomrcor = 0.96801

This gives an indication that the fit is good as we expected.

In Command 21, we calculated the denominator in Equation (7.9). Notice that instead of calculating the square of the standard deviation, we simply use the variance found with `var`

. From Equation (7.9), we see that the 2-norm of the residuals enters the nominator. This is already calculated in `polyfit`

and stored in the structure field `normr`

, so we use this in the evaluation of the ...

Start Free Trial

No credit card required