Calculations

One of the advantages of having a multiple choice exam is that I get abundant feedback on how many people got every question right, what proportion picked each answer etc. I was looking through the results of last years exam as preparation for writing this years and although I had always realized that people found genetic problems difficult I didn't realize the magnitude of the effect until I decided to quantify it.

If I crudely divide the questions up into three categories and calculate the average percentage of people that got questions in that category correct I get something like:

Genetic problems requiring calculations - 54%
Genetic problems requiring just logic or punnet squares etc - 73%
Everything else - 82%

Another way of looking at this is that although only perhaps ten questions fall into the first two categories the average person will lose 1/3 of the total points they lose on these ten questions alone. Hmmm.