Given the information below: Consider the following population regression function: where Ag and , denote the intercept and the slope coefficient on X, respectively. Let and B, denote the predicted intercept and the predicted slope coefficient, respectively Which of the following are the requirements for ensuring that there is no threat to internal validity in this case? O There is no difference between the population studied and the population of interest. O There is no difference between the settings studied and the settings of interest. The OLS estimator, B1 is an unbiased and consistent estimator of the population coefficient, B1. None of the above. Given the information below: Suppose we have a regression equation of the form: Y=Bo+BX+ B2X+3X3+...+X+u, i=1...n where Bo. P. B are the population coefficients. Let Bo. B... B, denote the respective estimated coefficients. Which of the following statements is not an implication of the regression error being correlated across observations? O The OLS estimators become biased and inconsistent. The regressors are not independently and identically distributed (i.i.d.) draws from their joint distribution. The heteroskedasticity-robust OLS standard errors are correct but the homoskedasticity-only OLS standard errors are incorrect. The external validity of the analysis is threatened. Suppose that you have just read a careful statistical study of the effect of advertising on the demand for cigarettes. Using data from New York during the 1970s, the study concluded that advertising on buses and subways was more effective than print advertising. Use the concept of external validity to determine if these results are likely to apply to Boston in the 1970s; Los Angeles in the 1970s; New York in 2010. O The results are likely to apply to Los Angeles in the 1970s, but not to Boston in the 1970s or to New York in 2010. The results are likely to apply to New York in 2010, but not to Boston in the 1970s or to Los Angeles in the 1970s. O The results are likely to apply to Boston in the 1970s, but not to Los Angeles in the 1970s or New York in 2010. The results are likely to apply to any city in the United States regardless of location and year