Answer: 62.
Step-by-step explanation: The mean is the average. In order to find the average, we need to add all of the numbers up, then divide by the number of quizzes. So:
20 + 40 + 40 +40 + 60 + 60 + 60 + 60 + 80 + 80 + 80 + 80 + 100 = 800
800 / 13 = 61.5, appr. 62.
