a cross-section from 1998
number of observations : 11130
observation : individuals
country : United States
A dataframe containing :
average hourly earnings
a factor with levels (male,female)
Bureau of labor statistics, U.S. Department of Labor http://www.bls.gov.
Stock, James H. and Mark W. Watson (2003) Introduction to Econometrics, Addison-Wesley Educational Publishers, chapter 3.