Brown and Casey hold double-digit advantages among self-identified independent voters, while in Florida Republican Mack leads Nelson among independents, 43 percent to 40 percent, a virtual tie. The polls are the first in a series of surveys conducted by Quinnipiac, in cooperation with its new media partners. All three polls were conducted July 24-30. The Florida poll surveyed 1,177 likely voters, 1,193 likely Ohio voters were interviewed and 1,168 likely voters in Pennsylvania were questioned. The margins of error for the Florida and Pennsylvania polls are plus-or-minus 2.9 percentage points for each survey; the margin of error for the Ohio poll is plus-or-minus 2.8 percentage points.