Imagine that you are hired by your state government to evaluate the eftectiveness of a publicly funded job training program．Suppose this program teaches workers various ways to use computers in the manufacturing process．The twenty—week program offers courses during nonworking hours．Any hourly manufacturing worker may participate，and enrollment in all or part of the program is voluntary．YoU are to determine what．if any，effect the training program has on each worker’S subsequent hourly wage．
  NOW suppose you work for an investment bank．YoU are to study the returns on different investment strategies involving short—term U．S．treasury bills to decide whether they comply with implied economic theories．
  The task of answering such questions may seem daunting at first．At this point，you may only have a vague idea of the kind of data you would need to collect．By theend of this introductory econometrics course．you should know how to use econometric methods to formally evaluate a job training program or to test a simple economic theory．
  Econometrics is based upon the development of statistical methods for estimating economic relationships，testing economic theories，and evaluating and implementing government and business policy．The most common application of econometrics is the forecasting of such important macroeconomic variables as interest rates．inflation rates. and gross domestic product．While forecasts of economic indicators are highly visible and are often widely published，econometric methods can be used in economic areas that have nothing to do with macroeconomic forecasting．For example，we will study
the effects of political campaign expenditures on voting outcomes．We will consider the effect of school spending on student performance in the field of education．