Yes, my last Statistics class was a couple of years ago, hence the somewhat wondering in dark.

From what I've read I need to use the chi square statistic, which is a sum of differences between observed and expected outcome frequencies, each squared and divided by the expectation:

The degrees of freedom df = (rows-1)(columns-1)

My problem is that, my degrees of freedom is = (1200-1)(2-1) = 1200

All the tables I've seen only go up to 9 or so df's.

Mr F says: Then you're looking in the wrong places. Tables of critical values routinely go up to 100 degrees of freedom. See PlanetMath: table of critical values of chi-squared distributions for example.
Does this mean I should just take a random sample of 10 measurements and apply it to that rather than the entire data set?

Thanks for your patience.