Consider this argument offered by the assistant principal of a high school: "fact is 99% of the time when a high school gets a bomb threat it is because some kid is not prepared to take an exam that day. our school just received a bomb threat. so this means that one of our students is not prepared to take an exam today." that argument is an example of

This argument is an example of a fallacy of composition.

Explanation:

The fallacy of composition is a fallacy that occurs whenever it is admitted that what is true for one part of the system is then true for the whole as well. We can take as an example the case described in the question above, where the headmaster of a high school assumed that the bomb threat in his high school was made by a student who did not study enough for an exam, because in many schools, students who did not study for their exams made bomb threats.