截面与面板数据析-复旦2.ppt

Analysis of Cross Section and Panel Data Yan Zhang School of Economics, Fudan University CCER, Fudan University Introductory Econometrics A Modern Approach Yan Zhang School of Economics, Fudan University CCER, Fudan University Analysis of Cross Section and Panel Data Part 1. Regression Analysis on Cross Sectional Data Chap 2. The Simple Regression Model——Practice for learning multiple Regression Bivariate linear regression model :the slope parameter in the relationship between y and x holding the other factors in u fixed; it is of primary interest in applied economics. :the intercept parameter, also has its uses, although it is rarely central to an analysis. More Discussion :A one-unit change in x has the same effect on y, regardless of the initial value of x. Increasing returns: wage-education (f. form) Can we draw ceteris paribus conclusions about how x affects y from a random sample of data, when we are ignoring all the other factors? Only if we make an assumption restricting how the unobservable random variable u is related to the explanatory variable x Classical Regression Assumptions Feasible assumption if the intercept term is included Linearly uncorrelated zero conditional expectation Meaning = 内生性 PRF (Population Regression Function): sth. fixed but unknown OLS Minimize uu sample regression function (SRF) The point is always on the OLS regression line. OLS Coefficient of determination the fraction of the sample variation in y that is explained by x. the square of the sample correlation coefficient between and Low R-squareds Units of Measurement If one of the dependent variables is multiplied by the constant c—which means each value in the sample is multiplied by c—then the OLS intercept and slope estimates are also multiplied by c. If one of the independent variables is divided or multiplied by some nonzero constant, c, then its OLS slope coef