We have no information on how the data was collected. If a death wasn't right before an exam, likely students wouldn't bother telling the professor. My grandpa

We have no information on how the data was collected. If a death wasn't right before an exam, likely students wouldn't bother telling the professor. My grandpa died last term and I didn't tell any professors. The measured death rate before exams should be compared to the expected death rate. How old is the average student, how old is their average grandma, and how many women from that period are expected to die at that age, multiplied by the fraction of the year taken up by the exam period.