Question 5. Match the following 4 concepts to the study design that is associated with it. Note that CIR (cumulative incidence ratio) is a synonym for relative risk; IDR (incidence density ratio) is a synonym for rate ratio Concept Study design a. Good way to estimate CIR when baseline 1. Prospective Cohort study specimens are expensive to test b. Permits blinding of treatment allocation 2. Nested case-control study c. Observe exposure status at start of study 3. Case-cohort study d. Estimates IDR for rare diseases 4. Randomized trial