Summary statistics for stch1997 dataset : by Jean Roth , jroth@nber.org , 17 Oct 2016 Variable | Obs Mean Std. Dev. Min Max -------------+--------------------------------------------------------- agegroup | 954,864 9 5.477228 0 18 racesex | 954,864 4.5 2.291289 1 8 ethnic | 954,864 1.5 .5000003 1 2 pop | 954,864 285.5348 2005.623 0 208885 year | 954,864 1997 0 1997 1997 -------------+--------------------------------------------------------- state | 0 county | 0 by Jean Roth , jroth@nber.org , 17 Oct 2016