In another study, the smoking habits of 34,445 male physicians were obtained by mailed questionnaires. Deaths among these physicians over the subsequent years were identified though contact with the office of the Registrar General. The death rates from lung cancer of these physicians classified by smoking habits were :

Question

In another study, the smoking habits of 34,445 male physicians were obtained by mailed questionnaires.  Deaths among these physicians over the subsequent years were identified though contact with the office of the Registrar General.  The death rates from lung cancer of these physicians classified by smoking habits were : 
Standardized Death Rates per 1000 Persons Aged 35 or More per Year
Nonsmokers					0.07
Cigarette Smokers				0.96

a. Name the type of study.
b. Calculate the Relative Risk for smokers as compared to nonsmokers.

c. Interpret the results