I think this is a trick riddle now that I realize it, because if the stat's are true, kindegarten's are not smarter than Harvard student's, and are most likely very lazy, and did not even care, because they couldn't fully comprehend.
So the trick lie's at the end. if this is true, and the stat's are really correct, like I said, there is no real answer, but just an answer to trick you. It was lying infront of us, the whole time.
So back to the riddle, and to the end of the riddle, I leave you with this.
Can you guess the riddle?