1. The following table gives the results of a study of smoking and a specific type of cancer. (50 points)

Initial Survey Amount of cigarettes smoked and the number (%) of subjects		Follow-up period
Amount	Number (%)	Number of subjects followed for 15 years (%)*	Number of cancer cases**
None	2240 (37.6)	2100 (93.8)	15
Ex-Smoker	1500 (25.2)	1230 (82.0)	20
1-19 / day	1260 (21.1)	950 (75.4)	44
20+ / day	960 (16.1)	603 (62.8)	50
Total	5960 (100)	4883 (81.9)	129

* percentage of those examined at the initial survey; assume that those lost to follow up were lost at 7 years*

**assume that all cases were identified at 15 year timepoint

1. What type of study is this? What branch of Epidemiology would it fall under?
2. Calculate the cumulative incidence per 1,000 persons per year, and incidence rate for all enrolled in each group in the table above. (Attach calculations for full credit)
3. Calculate and interpret the Relative Risk for development of cancer among ex-smokers compared to non-smokers among all enrolled or all followed. (Attach calculations for full credit)