Last couple of days I have attempted to re-educate myself on some of the concepts of statistics that I have long forgotten in the hope that I could reach a level of comprehension sufficient enough to model the relationships between variables and apply the formulas to economic forecasting. After a couple of days I feel overwhelmed by it all. I'm wondering if someone here can help me with lagged variables and how to compute the correlation using a program like R or Gretl. For example, the effect things like bank loan growth and money supply have on inflation.

Thank you

Matt