Residual plots 残差散点图 Residuals vs y a May need to transform Y variable Residuals VS XI a May need to transform X variable Residuals Vs x2 a May need to transform X, variable Residuals vs time 口 May have autocorrelation(自回归)Residual Plots 残差散点图 • Residuals Vs Yi  May need to transform Y variable • Residuals Vs X1  May need to transform X1variable • Residuals Vs X2  May need to transform X2 variable • Residuals Vs Time  May have autocorrelation（自回归） 