Question: whats a epidemiologist?

Wei Xun answered on 14 Jun 2011:

Epidemiology is the study of human populations. We aim to look at how diseases affect people by looking at what causes them.

So an epidemiologist may look at infectious agents eg colds, flus, viruses and how they spread in populations. Whereas I look for things that can cause cancer and for people to die earlier than they should.