Frequencies for first 10,000 rows of electrol variable in nhamcsopd2003 dataset : electrolyte | s | Freq. Percent Cum. ------------+----------------------------------- no | 9,634 96.34 96.34 yes | 366 3.66 100.00 ------------+----------------------------------- Total | 10,000 100.00 by Jean Roth , jroth@nber.org , 28 Mar 2016