EXST7015 : Statistical Techniques II Geaghan Multiple Regression Large example and Variable selection Page 1 08d-MReg-SENIC.doc 1 ***********************************************************************; 2 *** SENIC hospital study from Appendix C of: ***; 3 *** Neter, J., Kutner, M. H., Nachtsheim, C. J., and Wasserman, W., ***; 4 *** Applied Linear Statistical Models, 4th Edition, Richard D. ***; 5 *** Irwin, Inc., Burr Ridge, Illinois, 1996. ***; 6 ***********************************************************************; 7 OPTIONS PS=256 LS=121 NOCENTER NODATE NONUMBER; 8 9 DATA SENIC; Infile cards missover; 10 TITLE1 'SENIC database from NKNW 1996 (Appendix C)'; 11 INPUT IDNo LtofStay Age InfRisk CulRatio XRay NoBeds MedSch Region Census Nurses Services; 12 *** label IDNo = 'Identification number' 13 LtofStay = 'Length of stay (days)' 14 Age = 'Patient age (years)' 15 InfRisk = 'Average Infection risk (%)' 16 CulRatio = 'ratio cultures to patients w/o symptoms' 17 XRay = 'ratio xrays to patients w/o symptoms' 18 NoBeds = 'Average no. of beds in hosp.' 19 MedSch = 'Med School Affiliation' 20 Region = 'Region NE, NC, S, W' 21 Census = 'Average no. patients in hosp.' 22 Nurses = 'Av. no. nurses' 23 Services = '% of 35 potential service facilities'; 24 CARDS; NOTE: The data set WORK.SENIC has 113 observations and 12 variables. NOTE: DATA statement used: real time 0.30 seconds cpu time 0.12 seconds 24 ! Run; 138 ; 139 Proc print data=SENIC; RUN; NOTE: There were 113 observations read from the data set WORK.SENIC. NOTE: The PROCEDURE PRINT printed page 1. NOTE: PROCEDURE PRINT used: real time 0.26 seconds cpu time 0.09 seconds SENIC database from NKNW 1996 (Appendix C) Ltof Inf Cul No Med Obs IDNo Stay Age Risk Ratio XRay Beds Sch Region Census Nurses Services 1 1 7.13 55.7 4.1 9.0 39.6 279 2 4 207 241 60.0 2 2 8.82 58.2 1.6 3.8 51.7 80 2 2 51 52 40.0 3 3 8.34 56.9 2.7 8.1 74.0 107 2 3 82 54 20.0 4 4 8.95 53.7 5.6 18.9 122.8 147 2 4 53 148 40.0 5 5 11.20 56.5 5.7 34.5 88.9 180 2 1 134 151 40.0 6 6 9.76 50.9 5.1 21.9 97.0 150 2 2 147 106 40.0 7 7 9.68 57.8 4.6 16.7 79.0 186 2 3 151 129 40.0 8 8 11.18 45.7 5.4 60.5 85.8 640 1 2 399 360 60.0 9 9 8.67 48.2 4.3 24.4 90.8 182 2 3 130 118 40.0 10 10 8.84 56.3 6.3 29.6 82.6 85 2 1 59 66 40.0 . . . 109 109 11.80 53.8 5.7 9.1 116.9 571 1 2 441 469 62.9 110 110 9.50 49.3 5.8 42.0 70.9 98 2 3 68 46 22.9 111 111 7.70 56.9 4.4 12.2 67.9 129 2 4 85 136 62.9 112 112 17.94 56.2 5.9 26.4 91.8 835 1 1 791 407 62.9 113 113 9.41 59.5 3.1 20.6 91.7 29 2 3 20 22 22.9EXST7015 : Statistical Techniques II Geaghan Multiple Regression Large example and Variable selection Page 2 08d-MReg-SENIC.doc 140 proc reg data=SENIC all LINEPRINTER; 141 TITLE2 'Full Model with diagnostics'; 142 model InfRisk = LtofStay Age CulRatio XRay NoBeds Census Nurses Services 143 / all influence collin partial; 144 output out=next1 p=YHat r=e; 145 OPTIONS PS=50 LS=160; PLOT RESIDUAL.*PREDICTED. / VREF=0; 146 OPTIONS PS=60 LS=120; 147 Run; NOTE: 113 observations read. NOTE: 113 observations used in computations. 148 OPTIONS PS=50 LS=130; NOTE: The data set WORK.NEXT1 has 113 observations and 14 variables. NOTE: The PROCEDURE REG printed pages 2-28. NOTE: PROCEDURE REG used: real time 0.63 seconds cpu time 0.22 seconds 149 proc plot data=next1; PLOT e*YHat / VREF=0; 150 run; 151 OPTIONS PS=256 LS=121; 152 NOTE: There were 113 observations read from the data set WORK.NEXT1. NOTE: The PROCEDURE PLOT printed page 29. NOTE: PROCEDURE PLOT used: real time 0.02 seconds cpu time 0.01 seconds SENIC database from NKNW 1996 (Appendix C) Full Model with diagnostics The REG Procedure Descriptive Statistics Uncorrected Standard Variable Sum Mean SS Variance Deviation Intercept 113.00000 1.00000 113.00000 0 0 LtofStay 1090.26000 9.64832 10928 3.65366 1.91146 Age 6015.20000 53.23186 322430 19.90594 4.46161 CulRatio 1784.60000 15.79292 39916 104.74924 10.23471 XRay 9224.00000 81.62832 794935 374.95776 19.36383 NoBeds 28495 252.16814 11350621 37188 192.84269 Census 21625 191.37168 6786317 23642 153.75956 Nurses 19577 173.24779 5563895 19395 139.26539 Services 4877.00000 43.15929 236367 231.06619 15.20086 InfRisk 492.10000 4.35487 2344.41000 1.79803 1.34091 Uncorrected Sums of Squares and Crossproducts Variable Intercept LtofStay Age CulRatio XRay Intercept 113 1090.26 6015.2 1784.6 9224 LtofStay 1090.26 10928.3862 58217.008