TATA memorial hospital conducted a cohort study on 7000 subjects who were smokers over a ten-year period& found 70 subjects developed lung cancer. Concurrent evaluation of general population in the catchment area of hospital, out of 7000 non-smoker subjects only 7 developed lung cancer. The RR for developing lung cancer is

TATA memorial hospital conducted a cohort study on 7000 subjects who were smokers over a tenyear period & found 70 subjects developed lung cancer, Thus, Iexp = × 1000 = 10 per thousand Also, concurrent evaluation of general population in the catchment area of hospital, out of 7000 non-smoker subjects only 7 developed lung cancer, Thus, Inon-exp = × 1000 = 1 per 1000 Therefore, RR = 10 per 1000/ 1 per 1000 = 10