1. The student probably did not get sufficient sleep in order to stay wake and properly pay attention in class.
2. To test this hypothesis, I would tell the student to get a couple more hours of sleep than their usual sleeping time. My hypothesis would be supported if the student managed to stay awake during class. My hypothesis would be wrong if the student fell asleep regardless of how many hours of sleep. Therefore, this would show that my hypothesis is falsified.
3. An example of an untestable, unfalsifiable explaination would be that the student is hearing lullabies in their head which make them fall asleep, that no one else but the student can hear.
