R/twoyear.R

In wooldridge: 115 Data Sets from "Introductory Econometrics: A Modern Approach, 7e" by Jeffrey M. Wooldridge

#' twoyear
#'
#' Wooldridge Source: T.J. Kane and C.E. Rouse (1995), Labor-Market Returns to Two- and Four-Year Colleges, American Economic Review 85, 600-614. With Professor Rouse’s kind assistance, I obtained the data from her web site at Princeton University. Data loads lazily.
#'
#' @section Notes: As possible extensions, students can explore whether the returns to two-year or four-year colleges depend on race or gender. This is partly done in Problem 7.9 but where college is aggregated into one number. Also, should experience appear as a quadratic in the wage specification?
#'
#' Used in Text: pages 140-143, 165, 261, 340
#'
#' @docType data
#'
#' @usage data('twoyear')
#'
#' @format A data.frame with 6763 observations on 23 variables:
#' \itemize{
#'  \item \strong{female:} =1 if female
#'  \item \strong{phsrank:} percent high school rank; 100 = best
#'  \item \strong{BA:} =1 if Bachelor's degree
#'  \item \strong{AA:} =1 if Associate's degree
#'  \item \strong{black:} =1 if African-American
#'  \item \strong{hispanic:} =1 if Hispanic
#'  \item \strong{id:} ID Number
#'  \item \strong{exper:} total (actual) work experience
#'  \item \strong{jc:} total 2-year credits
#'  \item \strong{univ:} total 4-year credits
#'  \item \strong{lwage:} log hourly wage
#'  \item \strong{stotal:} total standardized test score
#'  \item \strong{smcity:} =1 if small city, 1972
#'  \item \strong{medcity:} =1 if med. city, 1972
#'  \item \strong{submed:} =1 if suburb med. city, 1972
#'  \item \strong{lgcity:} =1 if large city, 1972
#'  \item \strong{sublg:} =1 if suburb large city, 1972
#'  \item \strong{vlgcity:} =1 if very large city, 1972
#'  \item \strong{subvlg:} =1 if sub. very lge. city, 1972
#'  \item \strong{ne:} =1 if northeast
#'  \item \strong{nc:} =1 if north central
#'  \item \strong{south:} =1 if south
#'  \item \strong{totcoll:} jc + univ
#' }
#' @source \url{https://www.cengage.com/cgi-wadsworth/course_products_wp.pl?fid=M20b&product_isbn_issn=9781111531041}
#' @examples  str(twoyear)
"twoyear"