@MaartenPunt From my understanding, each row in Byssinosis and Non.Byssinosis is the number of workers with the combination of the variables in that row of the data frame. So for example, in row 1 there were a total of 3 workers who had Byssinosis. Those 3 workers have been employed at the company for <10 years, are smokers, male, White, and worked in the most dusty work place. There were also 37 workers who did not have Byssinosis, and those 37 workers have been employed at the company for <10 years, are smokers, male, White, and worked in the most dusty work place.

@MaartenPunt This data was collected in 1973 from a large cotton textile company. There were a total of 5,419 workers so if you add up the columns of Byssinosis and Non.Byssinosis you get 5,419.