This is not a cynical question, though it will sound that way. OK I have taken a bunch of stats courses, but I am not in the social or political sciences. How do you formulate a political poll that is unbiased, in a scientific sense? Or is that impossible? I know some build their sample based on historical demographic voting patterns. But that seems flawed. And some use census data, which I would guess is flawed for different reasons. But I am just trying to understand it more than anything. And I trust that here I will at least get pointed in the right direction for the answer.