White test was proposed by Halbert White in 1980. Tests whether regression model error variances are constant. Widely used and one of economics' most cited articles
Endogeneity occurs when explanatory variables are correlated with error terms. Simultaneity models distinguish variables determined by model from predetermined ones. Ignoring simultaneity leads to biased estimates violating Gauss-Markov theorem
Econometrics applies statistical methods to analyze economic relationships. Jan Tinbergen and Ragnar Frisch are among the founding fathers. Econometric theory combines theory and observation for quantitative analysis
Econometrics uses statistical models to develop and test economic theories. Pioneered by Klein, Frisch, and Kuznets, all Nobel Prize winners. Applied econometrics develops new hypotheses from existing data
Professor at Wellesley College for 30 years. Former Harvard Head Tutor, winning Allyn Young Teaching Prize. Research focuses on real estate, housing and public finance. Authored five books, including Principles of Economics. Co-authored book with Ray Fair, adopted by over 450 universities
Random variables summarize mutually exclusive outcomes of a process. Discrete variables have discrete outcomes, like dice rolls. Continuous variables take on continuum of possible values. Probability is proportion of outcome occurring in long run