what does i(tar(-1)) mean? what is treevolume in r what is treevol/cost in r what is the equation for treevol what is the r-squared of tree vol what is treevol mean in statistics what is the meaning of i(treevol) if treeVol is always constant what is the value of treevol what is i(treeval) in graph what is the coefficient for the regression analysis treevolume what the value of treevol in r treevol value r squared what does lm mean what is treevol what is the r squared value for i(value of treevol) if treeVol is true, then what is its r square? what does treevol mean in r what is i(var(-1) in r? i(treevolume -0.82)) meaning