I'm new to regression (vector autoregression), and recently encountered the following issue:
If I use raw dependent and independent variables to do the regression, the $R^2$, DW-d test and standard error of estimate for each dependent variable are quite good. The $R^2$ is above $95\%$.
However, When the dependent and independent variables are normalized to zero mean and unit variables (column normalized), these measures got worse. The $R^2$ ranges from $60\%-90\%$.
So what happened after I normalized the data?