Title 'Model Building using Backward Selection'. Data list fixed records=1 /1 gpa 1-3 greq 5-7 grev 9-11 mat 13-14 ar 16-18. begin data 3.2 625 540 65 2.7 4.1 575 680 75 4.5 3.0 520 480 65 2.5 2.6 545 520 55 3.1 3.7 520 490 75 3.6 4.0 655 535 65 4.3 4.3 630 720 75 4.6 2.7 500 500 75 3.0 3.6 605 575 65 4.7 4.1 555 690 75 3.4 2.7 505 545 55 3.7 2.9 540 515 55 2.6 2.5 520 520 55 3.1 3.0 585 710 65 2.7 3.3 600 610 85 5.0 3.2 625 540 65 2.7 4.1 575 680 75 4.5 3.0 520 480 65 2.5 2.6 545 520 55 3.1 3.7 520 490 75 3.6 4.0 655 535 65 4.3 4.3 630 720 75 4.6 2.7 500 500 75 3.0 3.6 605 575 65 4.7 4.1 555 690 75 3.4 2.7 505 545 55 3.7 2.9 540 515 55 2.6 2.5 520 520 55 3.1 3.0 585 710 65 2.7 3.3 600 610 85 5.0 end data. Regression variables=gpa,greq,grev,mat,ar /descriptives=mean,stddev,corr,n /statistics=r,anova,cha,coeff,ci,tol,history /dependent= gpa /method=backward. OUTPUT: 22 Dec 99 SPSS for Unix, Release 6.1 (AIX 3.2) Page 1 14:08:54 UCLA OAC IBM RS6000 AIX 3.2.5/4. For AIX 3.2.5/4. UCLA OAC SPSS ID 90095 * * * * M U L T I P L E R E G R E S S I O N * * * * Listwise Deletion of Missing Data Mean Std Dev Label GPA 3.313 .600 GREQ 565.333 48.618 GREV 575.333 83.034 MAT 67.000 9.248 AR 3.567 .838 N of Cases = 30 Correlation: GPA GREQ GREV MAT AR GPA 1.000 .611 .581 .604 .621 GREQ .611 1.000 .468 .267 .508 GREV .581 .468 1.000 .426 .405 MAT .604 .267 .426 1.000 .525 AR .621 .508 .405 .525 1.000 22 Dec 99 Model Building using Backward Selection Page 3 14:08:54 UCLA OAC IBM RS6000 AIX 3.2.5/4. * * * * M U L T I P L E R E G R E S S I O N * * * * Equation Number 1 Dependent Variable.. GPA Descriptive Statistics are printed on Page 2 Block Number 1. Method: Enter Variable(s) Entered on Step Number 1.. AR 2.. GREV 3.. MAT 4.. GREQ Multiple R .80030 Analysis of Variance R Square .64047 R Square Change .64047 DF Sum of Squares Mean Square Adjusted R Square .58295 F Change 11.13400 Regression 4 6.68313 1.67078 Standard Error .38738 Signif F Change .0000 Residual 25 3.75153 .15006 F = 11.13400 Signif F = .0000 ------------------------------------------ Variables in the Equation ------------------------------------------ Variable B SE B 95% Confdnce Intrvl B Beta Tolerance VIF T Sig T GREQ .003998 .001831 2.27987E-04 .007769 .324062 .653236 1.531 2.184 .0385 GREV .001524 .001050 -6.39208E-04 .003687 .210912 .680518 1.469 1.451 .1593 MAT .020896 .009549 .001230 .040562 .322145 .663614 1.507 2.188 .0382 AR .144234 .113001 -.088497 .376964 .201604 .576442 1.735 1.276 .2135 (Constant) -1.738107 .950740 -3.696192 .219979 -1.828 .0795 End Block Number 1 All requested variables entered. 22 Dec 99 Model Building using Backward Selection Page 4 14:08:54 UCLA OAC IBM RS6000 AIX 3.2.5/4. * * * * M U L T I P L E R E G R E S S I O N * * * * Equation Number 1 Dependent Variable.. GPA Block Number 2. Method: Backward Criterion POUT .1000 Variable(s) Removed on Step Number 5.. AR Multiple R .78552 Analysis of Variance R Square .61704 R Square Change -.02343 DF Sum of Squares Mean Square Adjusted R Square .57286 F Change 1.62917 Regression 3 6.43866 2.14622 Standard Error .39204 Signif F Change .2135 Residual 26 3.99601 .15369 F = 13.96436 Signif F = .0000 ------------------------------------------ Variables in the Equation ------------------------------------------ Variable B SE B 95% Confdnce Intrvl B Beta Tolerance VIF T Sig T GREQ .004926 .001701 .001430 .008421 .399215 .775329 1.290 2.896 .0076 GREV .001612 .001060 -5.67631E-04 .003792 .223171 .683502 1.463 1.520 .1405 MAT .026119 .008731 .008172 .044067 .402666 .812902 1.230 2.991 .0060 (Constant) -2.148770 .905406 -4.009858 -.287682 -2.373 .0253 ----------- not in ------------ Variable Tolerance VIF AR .576442 1.735 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * Variable(s) Removed on Step Number 6.. GREV Multiple R .76355 Analysis of Variance R Square .58300 R Square Change -.03404 DF Sum of Squares Mean Square Adjusted R Square .55211 F Change 2.31121 Regression 2 6.08344 3.04172 Standard Error .40144 Signif F Change .1405 Residual 27 4.35122 .16116 F = 18.87433 Signif F = .0000 22 Dec 99 Model Building using Backward Selection Page 5 14:08:54 UCLA OAC IBM RS6000 AIX 3.2.5/4. * * * * M U L T I P L E R E G R E S S I O N * * * * Equation Number 1 Dependent Variable.. GPA ------------------------------------------ Variables in the Equation ------------------------------------------ Variable B SE B 95% Confdnce Intrvl B Beta Tolerance VIF T Sig T GREQ .005976 .001591 .002712 .009241 .484382 .928761 1.077 3.756 .0008 MAT .030807 .008365 .013645 .047970 .474943 .928761 1.077 3.683 .0010 (Constant) -2.129377 .927038 -4.031501 -.227253 -2.297 .0296 ----------- not in ------------ Variable Tolerance VIF GREV .683502 1.463 AR .578970 1.727 End Block Number 2 POUT = .100 Limits reached. * * * * * * * * * * * * * * * * * * * * * * * * * * * * * Summary table ------------- Step MultR Rsq AdjRsq F(Eqn) SigF RsqCh FCh SigCh Variable BetaIn Correl 1 In: AR .6207 .6207 2 In: GREV .3947 .5815 3 In: MAT .2900 .6042 4 .8003 .6405 .5829 11.134 .000 .6405 11.134 .000 In: GREQ .3241 .6111 5 .7855 .6170 .5729 13.964 .000 -.0234 1.629 .214 Out: AR .6207 6 .7635 .5830 .5521 18.874 .000 -.0340 2.311 .141 Out: GREV .5815 22 Dec 99 Model Building using Backward Selection Page 6 14:08:54 UCLA OAC IBM RS6000 AIX 3.2.5/4. Preceding task required .05 seconds CPU time; .11 seconds elapsed. 41 0 40 command lines read. 0 errors detected. 0 warnings issued. 0 seconds CPU time. 0 seconds elapsed time. End of job.