2) Consider the following data from a hypothetical case control study examining the relationship between tanning bed use in young adulthood and risk of melanoma

History of Tanning Bed Use	Cases	Controls
Yes	632	316
No	202	808

a) Name the appropriate measure of association for estimating the relative risk of melanoma, comparing tanning bed users (exposed) to nonusers (reference category) (1pt). Calculate this measure (2pts) and provide a brief interpretation of your answer (1pt)

b) Assume that this relationship is causal. Among young people who use tanning beds, what proportion of melanoma risk could be eliminated by banning tanning bed use in young adults? (2pts)

c) If 5% of all young adults use tanning beds, what proportion of melanoma risk could be eliminated from the overall general population by banning the use of tanning beds in young adults? (2pts)

d)In a refinement to the original analysis, the investigators decided to categorize tanning bed use according to hours of lifetime exposure:

History of Tanning Bed Use (lifetime hours)	Cases	Controls	Measure of Association
None	202	808	1.0 (reference)
1 - 10hrs	281	169
11 - 20hrs	198	96
>20hrs	153	51

Calculate the appropriate measure of association for each of the three categories of tanning bed use, using "None" as the reference category (1pt each)

1 - 10hrs:

11 - 20hrs:

>20hrs: