Number of smokers in a case-control study.
data(Smoking_SchairerSchoeniger1944)
The format is: table [1:5, 1:7] 3 11 31 19 29 2 0 4 6 3 ... - attr(*, "dimnames")=List of 2 ..$ Smoking : chr [1:5] "Nonsmoker" "Moderate smoker" "Medium smoker" "Heavy smoker" ... ..$ Diagnosis: chr [1:7] "Lung cancer" "Lip cancer" "Throat cancer" "Stomach cancer" ...
Richard Doll (1998), Uncovering the effects of smoking: historical perspective. Statistical Methods in Medical Research, 7(87), 87-117