quiz#1: Older epidemiologic studies show that condom use does not protect against infection with Human Papiloma Virus (HPV). However, newer studies show that condoms are protective. Why is that?

--------------------------------------------------------------

Quiz#2: You want to estimate the prevalence of hepatitis among IV drug users. You sample participants in the mobile fixing room at Vesterbro. Participants are bled which makes you determine if they are infected or not.

--------------------------------------------------------------

Quiz#3: You want to find out whether children of medical doctors are more often accepted in medical school than kids of non-doctors.In a case-control study you sample 200 applicants who were accepted (cases) and 200 applicants who were not accepted (controls). You ask them if they are doctor-kids (exposed) or not (unexposed).