In a cohort study of smoking and lung cancer, the incidence of lung cancer among smokers was found to be 9/1,000 and the incidence among non-smokers was 1/1,000. From another source we know that 45% of the total populations were smokers.
what is the incidence of lung cancer attributable to smoking in the total population
and what is the proportion of the risk in the total population that is attributable to smoking.