Frequencies for first 10,000 rows of electrol variable in nhamcsopd2005 dataset : electrolyte | s | Freq. Percent Cum. ------------+----------------------------------- no | 9,164 91.64 91.64 yes | 836 8.36 100.00 ------------+----------------------------------- Total | 10,000 100.00 by Jean Roth , jroth@nber.org , 28 Mar 2016