Vocab data frame has 21,638 rows and 5 columns.
The observations are respondents to U.S. General Social Surveys, 1972-2004.
This data frame contains the following columns:
Year of the survey.
Sex of the respondent,
Education, in years.
Vocabulary test score: number correct on a 10-word test.
National Opinion Research Center General Social Survey. GSS Cumulative Datafile 1972-2004, downloaded from http://sda.berkeley.edu/archive.htm.
Fox, J. (2008) Applied Regression Analysis and Generalized Linear Models, Second Edition. Sage.
Fox, J. and Weisberg, S. (2011) An R Companion to Applied Regression, Second Edition, Sage.