代写ECN 522、ECN 522留学生代写、c/c++程序语言代做、代写Java/Python代写

日期：2019-05-10 11:03

ECN 522 Spring 2018

Problem Set 6

Due in class by 12:30pm March 27th.

Problem 1

This problem uses the geocol 24-26.dta on Blackboard, which contains wage and other information about

24-26 year old males from a 1976 survey. You can use the command "describe" to check the deanitions of

the variables.

1. Regress wage on ed, black, and exp variables and interpret all of the regression coe￠ cients.

2. Generate a new variable nonblack=1-black in Stata. (use the command "generate") Run a regression

of wage on ed, nonblack and exp and comment on the results. What happens to the intercept of the

regression? Now run a regression of wage on ed, exp, and both black and nonblack dummy variables

and comment on the results. Next, run the same regression but omitting the intercept. Can you

interpret the coe￠ cients on the black and nonblack dummy variables? the di§erence between them?

Be precise.

3. Variable kww is the personís test score on the "Knowledge of the World of Work" test. Regress wage

on ed, black, exp, and kww. Comment on what happens with the coe￠ cient on ed. Variable kww2 uses

the same test answers as the variable kww but weights test questions slightly di§erently. Calculate the

correlation between kww and kww2. Regress wage on ed, black, exp, and kww2. Then regress wage

on ed, black, exp, kww, and kww2 and comment on the results, in particular on the standard errors

of the coe￠ cients on kww and kww2.

4. In the regression of wage on ed, black, exp, kww, kww2, test the null hypothesis that the test scores

kww and kww2 do not help explaining wage. Do this by using heteroskedasticity robust F-statistic

and the "test" command in Stata, and then by using homoskedasticity only formulas for the F-statistic

using R2 of restricted and unrestricted regressions. Finally, using the "test" command in Stata, test

the hypothesis that the null coe￠ cients on kww and kww2 are equal.

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