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.