data d; input Day Temp RH; label Day = "Reaction Day (Hours)" Temp = "Temperature (Degrees Centigrade)" RH = "Percent of humidity"; datalines; 11 26 62 13 22 75 10 25 62 14 22 75 10 26 62 14 22 75 11 26 62 11 22 75 14 27 95 8 30 75 8 24 80 13 27 95 6 30 75 8 24 80 12 27 94 7 30 75 6 24 80 14 27 95 7 30 75 8 24 80 ; ods graphics on; proc rsreg data=d plots=(ridge surface); model Day=RH Temp / lackfit; ridge max; run; ods graphics off; Greeting All I used rsreg in multiple regression to find which model is the best I got linear with 0.2825 R-Square and Quadratic 0.6200 R Square Is there a way to write an equation based combine the linear model with the Quadratic? Best regards Samir ... View more

options pageno=1 linesize=80; goptions reset=all; title "Multiple regression for shelf_life"; data shelf_life; input Temp RH Days; datalines; 10 94 65 10 93 51 10 94 70 9 93 78 ; run; * Print data set; proc print data= shelf_life; run; * Plot y vs. x variables; proc gplot data=shelf_life; plot Days*(Temp RH ); symbol1 i=rl v=star c=black; run; * Multiple regression analysis; ods html; ods graphics on; proc reg data=shelf_life; * Specify regression model and request residual-residual plots; model Days = Temp RH / clb stb partial tol selaction=RSquare; run; Plot r.*pred. r.*nqq.; run; quit; proc reg data=shelf_life; * Specify regression model and request residual-residual plots; model Days = Temp / clb stb partial tol selaction=RSquare; run; ods graphics off; ods html close; quit; Greeting All I used multiple regression and I got high R Square with non-significant. How I can write the equation The code was attached under the name Shelf-life1.   Best Regards Samir     ... View more