Frequencies for first 10,000 rows of blodpres variable in namcs1998 dataset : blood | pressure | test | Freq. Percent Cum. ------------+----------------------------------- 0 | 5,296 52.96 52.96 1 | 4,704 47.04 100.00 ------------+----------------------------------- Total | 10,000 100.00 by Jean Roth , jroth@nber.org , 28 Mar 2016