Interesting Pa. Exit Poll Datum:
9% of the voters in the Pennsylvania primary were African Americans who said race was not a factor in their vote. Of those 9%, 91% voted for Barack Obama, exactly the same as the overall African American percentage for Obama, including the 4+% who said race was a factor in their vote (the poll doesn't give a breakdown of the exact percentages for the latter group, but it can't be very different than 91-9).
By contrast, both men and women (especially women) who said that "gender" was a factor in their vote were significantly more likely to vote for Clinton. And whites who said race was a factor in their vote were significantly more likely to vote for Clinton.