Single equation regression models: -The dependent variable, Y, is expressed as a linear function of one or more explanatory variables, the Xs. Assumption the cause-and-effect relationship, if any, between Y and the Xs is unidirectional: explanatory variables are the cause; the dependent variable is the effect
11.1 The Nature of Heteroscedasticity Homoscedasticity: equal variance. Heteroscedasticity: unequal variance. Heteroscedasticity is usually found in cross-sectional data
Multiple Regression Model: A regression model with more than one explanatory variable, multiple because multiple nfluences (i.e., variables)affect the dependent variable