sysuse auto quietly regress weight displacement graph twoway (scatter weight disp) (lfit weight disp), /// text(2750 350 "y = {&beta}{sub:0} + {&beta}{sub:1} * x" " " /// "weight = `:di %4.0f =_b[_cons]' + `:di %3.1f = _b[displacement]' * displacement") /// ytitle("Weight (lbs.)") legend(off) title("Original") name(g1, replace) preserve quietly summarize displacement replace displacement = displacement - r(mean) label var displacement "{&Delta} displacement (cu. in.)" quietly regress weight disp graph twoway (scatter weight disp) (lfit weight disp), /// text(2750 150 "y = {&beta}{sup: {&Delta}}{sub:0} + {&beta}{sup: {&Delta}}{sub:1} * {&Delta}x" " " /// "weight = `:di %4.0f =_b[_cons]' + `:di %3.1f = _b[displacement]' * displacement") /// ytitle("Weight (lbs.)") legend(off) title("Centered") name(g2) quietly summarize displacement replace displacement = displacement/r(sd) label var displacement "{&sigma} displacement (std. dev.)" quietly regress weight disp graph twoway (scatter weight disp) (lfit weight disp), /// text(2750 1.5 "y = {&beta}{sup: {&sigma}}{sub:0} + {&beta}{sup: {&sigma}}{sub:1} * z" " " /// "weight = `:di %4.0f =_b[_cons]' + `:di %3.1f = _b[displacement]' * displacement") /// ytitle("Weight (lbs.)") legend(off) title("Standardized") name(g3) graph combine g1 g2 g3, name(linear) graph drop g1 g2 g3 restore preserve quietly regress weight c.displacement##c.displacement estimates store Original graph twoway (scatter weight disp) (qfit weight disp), /// text(2750 350 "y = {&beta}{sub:0} + {&beta}{sub:1}*x + {&beta}{sub:2}*x{sup:2}" " " /// "weight = `:di %4.0f =_b[_cons]' + `:di %3.1f = _b[displacement]'*displacement" /// " `:di %5.3f = _b[c.displacement#c.displacement]'*displacement{sup:2}") /// title("Original") name(g4) quietly summarize displacement replace displacement = displacement - r(mean) label var displacement "{&Delta} displacement (cu. in.)" quietly regress weight c.disp##c.disp estimates store Centered graph twoway (scatter weight disp) (qfit weight disp), /// text(2750 150 "y = {&beta}{sup: {&Delta}}{sub:0} + {&beta}{sup: {&Delta}}{sub:1}*x + {&beta}{sup: {&Delta}}{sub:2}*x{sup:2}" " " /// "weight = `:di %4.0f =_b[_cons]' + `:di %3.1f = _b[displacement]'*displacement" /// " `:di %5.3f = _b[c.displacement#c.displacement]'*displacement{sup:2}") /// title("Centered") name(g5) graph combine g4 g5, name(quadratic) graph drop g4 g5 restore estimates table Original Centered, se varwidth(15)