Doll And Hill first estimated the proposition that smoking was a risk factor for the lung cancer in a case-control study (Doll and Hill, 1950). They discovered that, of 650 men having lung cancer (cases), 645 had smoked at some time, in comparison with the 625 of 650 men without lung cancer (control).

a) Design a clearly labelled and appropriate 2 x 2 table to display these data.

b) How many times a smoker is more prone to develop lung cancer rather than a non-smoker?

c) Determine the proportion of the lung cancers attributable to smoking among

 i) smokers and

 ii) the whole population.

d) State what these measures are known as and how does their interpretation differ?