Records in the file "iowa_workers.txt" are comma-delimited.

The variables are:

male	1 if individual is male
	0 otherwise

age	(in years)

black	1 if individual is Black
	0 otherwise

asian	1 if individual is Asian
	0 otherwise

other	1 if individual's race is other than White, Black, or Asian
	0 otherwise

Note: the race categories are exclusive. "White" is the omitted base category.

hispanic
	1 if individual is Hispanic or Latino
	0 otherwise

Note: According to the Census Bureau conventions, "hispanic" is not a race category.

married	1 if individual is married with spouse present
	0 otherwise

hs_degree
	1 if individual's educational attainment is high school
	0 otherwise

col_degree
	1 if individual's educational attainment is college at an associate or bachelor's level
	0 otherwise

gr_degree
	1 if individual's educational attainment is college at a graduate level
	0 otherwise

Note: educational attainment categories represent the highest completed level of schooling.
      The omitted base category is "no high school degree."

weeks	number of weeks worked in 1999

hours	number of hours worked during a typical week in 1999

incws 	total wage and salary income in 1999 (in dollars