[Nemo]

Three classes are studying the same subject, but they have different teachers who give different tests.

Average Test Scores:
Class A: 20%
Class B: 50%
Class C: 80%

Question 1: Which group of students knows its subject the best?

Question 2: Which test was the most cleverly designed?

Answer: we don't know. Any combination of answers to the two questions is possible: it all depends on the questions asked on the tests. The class averages tell us very little.