This term I’m giving my second undergraduate lecture, on bio-statistics. Bio-statistics, for those who never heard of it, is just a pretty name for plain old basic statistics with a focus on biomedical applications.
Lecturing, specially giving such elementary-level classis, is a fascinating endeavor. It is really nice to try and read the students reactions to find out if they are following the subject, and trying to interact with all of them to keep them engaged in the class.
Today I was taking special note on how much time I should give students to answer the questions that I posed to the class. I like to make sample, easy questions to make students figure out part of the subject by themselves before explaining it, and review questions when I feel some subject can be better understood with an example.
Many students don’t even try to answer the questions, so you cannot wait forever: the class must go on. However, a very simple pitfall is to just give them the time you would expect yourself to answer that question. Even if the question is elementary, for most of the students it is the first time they are thinking about that subject, and they will obviously take on average more time than you would to answer the question. So you must wait more time than what your gut tells you to be necessary.
However, there is a more subtle pitfall: just waiting until the fastest students answer the question. In my class today, there were about three students who would answer my questions pretty quickly. At first, I would be satisfied with their answers and move on. But on one question I noticed that after these students had given me their answers, there were quite a few more students still scribbling in their scratchbooks. They were trying to answer the question by themselves, and I would do them a disservice if I moved on right away!
Of course, when the question requires calculation, it is pretty easy to find out how many students are still trying to answer the question. But on more conceptual questions, how can I tell if the students are still trying, or if most of them have given up already? One way is to use some “easy to read” questions and find out who are the “FTS!” students. Then I can concentrate on reading the expressions of those students who I know usually put effort in the class. But I would appreciate more ideas.