Increasing the number of independent variables in a regression A) will increase the SSR of the model. B) will improve the goodness-of-fit of the model. C) does not necessarily cause the R2 to increase or decrease. D) does not necessarily cause the R2 to increase or decrease. Endogeneity in the independent variables can come from A) omitted variables that are significant and are correlated with any existing independent variables. B) measurement errors in the independent variables C) simultaneous equations that jointly determine the dependent and the independent variables. D) All of the above. Consider the following TSLS model, where Ability is an endogenous independent variable, while Educ and Age are exogenous. Answer questions (8) and (9). Stage 1 : Ability = on + on * Educ + 02 * Age + 03 * Expr + a * Par Educ + as * KWW + V Stage 2 : log(Wage) = Po + 81 * Educ + 82 * Age + By * Ability + U The model is A) under-identified. B) just-identified. C) over-identified. D) none of the above. The included instrumental variable(s) is/are (i), and the excluded instrumental variable(s) is/are (ii). A) (i) Ability; (ii) Educ and Age B) (i) Educ and Age; (ii) Erpr ParEduc and KWW C) (i) Educ, Age, Expr ParEduc and KWW; (ii) none D) (i) Ability; (ii) Educ, Age, Erpr, ParEduc and KWW A (i) can be used to check for the validity of the over-identification, and a (ii) can be used to check for the relevance of the instrumental variables. A) (i) Sargan test; (ii) Hausman test B) (i) Sargan test; (ii) first-stage F test C) (i) first-stage F test; (ii) Hausman test D) (i) Hausman test; (ii) first-stage F test