It is really unfortunate that this class is most students first introduction to the field of epidemiology. While Professor Olsen may be a genius in the field, his teaching skills are nearly non-existent. After being in his class for more than a quarter, I feel that most students know little more than when we all began. His lectures are unclear and boring- he really might as well be speaking in another language. He seems much more concerned with the grade distribution than whether or not his student actually understand a single thing that's going on.
Your best bet to do well in this class is to not listen in lecture (seriously, it will only confuse you more), and study the TA handouts, as well as online resources (google, wikipedia, journal articles, whatever you can find). My next piece of advice would be to just do the best you can, and stick it out- fortunately the 200 series in just one year- then you can move on to electives that will teach you way more about the field.
This is an extremely disappointing class, but I would suggest, to minimize YOUR feelings of disappoint, to not expect to learn anything from Professor Olsen. Because you probably won't.