In 2008, Dems won 10 of the 18 House seats in Ohio and Obama won.
In 2012, Republicans currently hold 13 of 18 seats in Ohio.
But Ohio loses 2 seats in 2012.
If the GOP keeps its 11 seats, and if all those voting GOP for the House vote for Romney, does that guarantee Romney wins Ohio?
What are conditions sets for the GOP to win 10 or more seats in Ohio and Obama win Ohio?
Are those likely?
This is a lesson in fractions.
What data would you need to figure out how many people voted Republican for House and then voted for Obama?
Develop some graphs to help you analyze this.
This can be done for other states like Michigan, Pennsylvania, Wisconsin, Iowa, Virginia, and Colorado.
In Pennsylvania, Republicans have 12 of 19.
In 2008, Dems won 12 of 19 when Obama won Pennsylvania. If the GOP holds in the same ratio it has now, then Romney is likely to win. Work out analysis of this using fractions.
Make simple assumptions first and then discuss what is needed to get crossover votes or non-voting combinations to get the other candidate to win for president. Start by assuming each congressional district has the same number of votes cast and that each vote for a house party goes the same for president. Then work from that on how to explain a cross over vote for the state.