I'm knitting Obama a hat and then sending it to the white house. The problem is I don't know what hat size the president wears. I think by doing a poll, I will find the correct answer, because when lots of people guess, individual bias tends to cancel out. This is known as the wisdom of large crowds. For example, when a crowd of people were asked to guess the weight of a bull, the average guess of all those people was within 2% of the correct weight