What is the average of the squares of the first 5 counting numbers?

The squares are 1, 4, 9, 16 and 25, which add to 55, so the average is 55/5 = 11. 9 squares the average instead of averaging the squares: the average of 1 to 5 is 3 and 3 squared is 9. Squaring and averaging cannot be swapped round, which is why 9 and 11 differ. 13.75 is 55/4, dividing by one fewer than the five numbers actually listed. 25 is the largest square, not the average.