tailieunhanh - Quantitative Models in Marketing Research Chapter 3

3 A continuous dependent variable. In this chapter we review a few principles of econometric modeling, and illustrate these for the case of a continuous dependent variable. We assume basic knowledge of matrix algebra and of basic statistics and mathematics | 3 A continuous dependent variable In this chapter we review a few principles of econometric modeling and illustrate these for the case of a continuous dependent variable. We assume basic knowledge of matrix algebra and of basic statistics and mathematics differential algebra and integral calculus . As a courtesy to the reader we include some of the principles on matrices in the Appendix section . This chapter serves to review a eew issues which suould be usci iil for later chapters. In section we discuss the representation of the standard Linear Regression model. In section we discuss Ordinary Least Squares and Maximum Likelihood estimation in substantial detail. Even though the Maximum Likelihood method is not illustrated in detail its basic aspects will be outlined as we need it in later chapters. In section diagnostic measures for outliers residual autocorrelation and heteroskedasticity are considered. Model selection concerns the selection of relevant variables and the comparison of non-nested models using certain model selection criteria. Forecasting deals with within-sample or out-of-sample prediction. In section we illustrate several issues for a regression model that correlates sales with price and promotional activities. Finally in section we discuss extensions to multiple-equation models thereby mainly focusing on modeling market shares. This chapter is not at all intended to give a detailed account of econometric methods and econometric analysis. Much more detail can for example be found in Greene 2000 Verbeek 2000 and Wooldridge 2000 . In fact this chapter mainly aims to set some notation and to highlight some important topics in econometric modeling. In later chapters we will frequently make use of these concepts. The standard Linear Regression model In empirical marketing research one often aims to correlate a random variable Yt with one or more explanatory variables such as xt where 29 30 Quantitative models in marketing .