propval data frame: y x1 x2 x3 x4 x5 x6 x7 x8 x9 1 25.9 4.9176 1.0 3.4720 0.998 1.0 7 4 42 0 2 29.5 5.0208 1.0 3.5310 1.500 2.0 7 4 62 0 3 27.9 4.5429 1.0 2.2750 1.175 1.0 6 3 40 0 4 25.9 4.5573 1.0 4.0500 1.232 1.0 6 3 54 0 5 29.9 5.0597 1.0 4.4550 0.988 1.0 6 3 56 0 6 30.9 5.8980 1.0 5.8500 1.240 1.0 7 3 51 1 7 28.9 5.6039 1.0 9.5200 1.501 0.0 6 3 32 0 8 35.9 5.8282 1.0 6.4350 1.225 2.0 6 3 32 0 9 31.5 5.3003 1.0 4.9883 1.552 1.0 6 3 30 0 10 31.0 6.2712 1.0 5.5200 0.975 1.0 5 2 30 0 11 30.0 5.0500 1.0 5.0000 1.020 0.0 5 2 46 1 12 36.9 8.2464 1.5 5.1500 1.664 2.0 8 4 50 0 13 41.9 6.6969 1.5 6.9020 1.488 1.5 7 3 22 1 14 40.5 7.7841 1.5 7.1020 1.376 1.0 6 3 17 0 15 43.9 9.0384 1.0 7.8000 1.500 1.5 7 3 23 0 16 37.5 5.9894 1.0 5.5200 1.256 2.0 6 3 40 1 17 37.9 7.5422 1.5 5.0000 1.690 1.0 6 3 22 0 18 44.5 8.7951 1.5 9.8900 1.890 2.0 8 4 50 1 19 37.9 6.0831 1.5 6.7265 1.652 1.0 6 3 44 0 20 38.9 8.3607 1.5 9.1500 1.777 2.0 8 4 48 1 21 36.9 8.1400 1.0 8.0000 1.504 2.0 7 3 3 0 22 45.8 9.1416 1.5 7.3262 1.831 1.5 8 4 31 0 Forward Selection: Start: AIC=80.78 y ~ 1 Backward Selection: Start: AIC=58.41 y ~ x2 + x3 + x4 + x5 + x6 + x7 + x8 + x9 Df Sum of Sq RSS AIC - x9 1 0.356 138.46 56.469 - x4 1 3.541 141.64 56.970 - x6 1 6.019 144.12 57.351 138.10 58.413 - x7 1 13.930 152.03 58.527 - x8 1 14.813 152.91 58.654 - x3 1 16.077 154.18 58.835 - x5 1 53.008 191.11 63.560 - x2 1 67.404 205.50 65.157 Step: AIC=56.47 y ~ x2 + x3 + x4 + x5 + x6 + x7 + x8 Df Sum of Sq RSS AIC - x4 1 3.234 141.69 54.977 - x6 1 8.468 146.93 55.775 138.46 56.469 - x8 1 17.132 155.59 57.036 - x3 1 19.527 157.98 57.372 - x7 1 20.604 159.06 57.521 - x5 1 55.703 194.16 61.908 - x2 1 74.049 212.51 63.894 Step: AIC=54.98 y ~ x2 + x3 + x5 + x6 + x7 + x8 Df Sum of Sq RSS AIC - x6 1 8.820 150.51 54.306 141.69 54.977 - x7 1 17.790 159.48 55.579 - x8 1 19.841 161.53 55.861 - x3 1 33.202 174.89 57.609 - x5 1 57.809 199.50 60.505 - x2 1 128.513 270.20 67.179 Step: AIC=54.31 y ~ x2 + x3 + x5 + x7 + x8 Df Sum of Sq RSS AIC - x7 1 9.351 159.86 53.632 150.51 54.306 - x8 1 21.298 171.81 55.217 - x3 1 62.775 213.29 59.975 - x5 1 82.292 232.80 61.901 - x2 1 136.783 287.29 66.528 Step: AIC=53.63 y ~ x2 + x3 + x5 + x8 Df Sum of Sq RSS AIC 159.86 53.632 - x8 1 44.593 204.46 57.045 - x3 1 59.563 219.43 58.599 - x5 1 78.661 238.52 60.435 - x2 1 129.327 289.19 64.673 Stepwise Selection: Start: AIC=58.41 y ~ x2 + x3 + x4 + x5 + x6 + x7 + x8 + x9 Df Sum of Sq RSS AIC - x9 1 0.356 138.46 56.469 - x4 1 3.541 141.64 56.970 - x6 1 6.019 144.12 57.351 138.10 58.413 - x7 1 13.930 152.03 58.527 - x8 1 14.813 152.91 58.654 - x3 1 16.077 154.18 58.835 - x5 1 53.008 191.11 63.560 - x2 1 67.404 205.50 65.157 Step: AIC=56.47 y ~ x2 + x3 + x4 + x5 + x6 + x7 + x8 Df Sum of Sq RSS AIC - x4 1 3.234 141.69 54.977 - x6 1 8.468 146.93 55.775 138.46 56.469 - x8 1 17.132 155.59 57.036 - x3 1 19.527 157.98 57.372 - x7 1 20.604 159.06 57.521 - x5 1 55.703 194.16 61.908 - x2 1 74.049 212.51 63.894 Step: AIC=54.98 y ~ x2 + x3 + x5 + x6 + x7 + x8 Df Sum of Sq RSS AIC - x6 1 8.820 150.51 54.306 141.69 54.977 - x7 1 17.790 159.48 55.579 - x8 1 19.841 161.53 55.861 - x3 1 33.202 174.89 57.609 - x5 1 57.809 199.50 60.505 - x2 1 128.513 270.20 67.179 Step: AIC=54.31 y ~ x2 + x3 + x5 + x7 + x8 Df Sum of Sq RSS AIC - x7 1 9.351 159.86 53.632 150.51 54.306 - x8 1 21.298 171.81 55.217 - x3 1 62.775 213.29 59.975 - x5 1 82.292 232.80 61.901 - x2 1 136.783 287.29 66.528 Step: AIC=53.63 y ~ x2 + x3 + x5 + x8 Df Sum of Sq RSS AIC 159.86 53.632 - x8 1 44.593 204.46 57.045 - x3 1 59.563 219.43 58.599 - x5 1 78.661 238.52 60.435 - x2 1 129.327 289.19 64.673