QuadReg [Xlistname,Ylistname,freqlist,regequ]

Fits a quadratic regression model to Xlistname and Ylistname with frequency freqlist, and stores the regression equation to regequ.

QuartReg [Xlistname,Ylistname,freqlist,regequ]

Fits a quartic regression model to Xlistname and Ylistname with frequency freqlist, and stores the regression equation to regequ.