Linked from Real Clear Politics piece that says Obama's numbers are worse than Bush's at the same point in his presidency, but, from the poll intro . . . "Interviews with 1,136 adult Americans, including an oversample of African-Americans, conducted by telephone by Opinion Research Corporation on July 31-August 3, 2009." Why oversampling in that group? How much? And how bad are the numbers if the sampling is the normal 11%?