I am not sure I quite understand that? Is it because they vote in a larger percentage than other groups?
I am not sure I quite understand that? Is it because they vote in a larger percentage than other groups?
It's because of their residency patterns.
If you were to randomly dial 1000 numbers, making sure that you had X number from each area code, you would probably get the white population in proportion to its representation in the U.S. population. But not so for blacks. They are not spread out all over the country, but rather tend to live in urban population centers. For this reason, pollsters oversample them, then make an adjustment for having done so. This way they feel confident that they have surveyed enough people from the group to accurately capture their opinion while not not allowing the oversample to give them more representation than is actually the case.
I hope this makes sense. I know it can be confusing.