几个因素(自变量)有关:-|||-x1--初始断面的BOD浓度L0,-|||-x2--初始断面的氧亏浓度Co,-|||-x3--水温T,-|||-x4--河流流量Q,-|||-x5--排污口流量 g,-|||-x6--污水BOD浓度l,-|||-x7--流过该河段所需时间 t.-|||-共观测了15组数据(见表4.6),试用逐步回归或双重筛选逐步回归-|||-求出BOD浓度Y1、氧亏浓度Y2与x 1,x2,.,x2的回归方程.-|||-表4.6 水污数据-|||-序号 X1 X2 X3 X4 X5 X6 X7 Y1 Y2-|||-1 6.88 .-0.25 27.0 67.4784 1.1232 477.0 0.083 9.35 -2.66-|||-2 6.08 .-2.21 27.5 47.7792 1.1232 193.0 0.083 12.30 I -4.02-|||-3 2.14 .-3.04 26.0 47.7792 1.1232 404.0 0.083 15.60 .-4.59-|||-4 5.02 .-0.73 26.0 85.6224 1.1232 363.0 0.073 5.88 -3.96-|||-5 7.89 .-2.26 26.0 85.6224 1.1232 363.0 0.069 6.34 .-3.02-|||-6 2.38 !-1.65 15.0 149.0400 1.5552 428.0 0.104 4.00 .-1.74-|||-7 1.86 .-1.35 15.8 149.0400 1.5552 428.0 0.104 3.76 -1.47-|||-8 1.02 .-2.12 17.1 149.4720 1.3824 428.0 0.104 3.98 .-2.33-|||-9 1.22 .-1.92 17.5 149.4720 1.3824 428.0 0.104 3.98 !-2.19-|||-10 0.90 .-0.27 17.0 362.8800 0.9936 202.0 0.104 2.78 0.33-|||-11 2.58 .-0.09 17.0 362.8800 0.9936 202.0 0.104 1.88 0.23-|||-12 2.78 .-1.17 13.5 326.5920 0.9936 114.0 0.104 2.56 .-0.74-|||-13 2.10 .-1.30 13.5 326.5920 0.9936 114.0 0.104 2.72 .-0.80-|||-14 2.32 .-0.60 14.5 364.6080 0.8640 57.3 0.104 1.64 .-0.62-|||-15 2.96 .-0.60 14.5 364.6080 0.8640 57.3 0.104 2.36 .-0.32