Are exam grades classified as interval data or ratio data? Why? Keep in mind that in typical exams, a score of 0 means that you answered every question wrong (or didn’t answer the question at all). Does this  score indicate an absolute absence of knowledge? If Student A earns 40 percent on an exam and Student B earns 80 percent on the same exam, can we assume that, compared to Student A, Student B knows twice as much about the subject?