A simple Chi-square calculator for two samples

The program is here

Download and install the simple Chi-square analysis program. The sample data are from the 2004 election where self-identified Bush and Kerry supporters were asked a number of questions. The analysis will show if either of the two populations were more badly informed than the other. The null hypothesis is that both are equally misinformed. For the first question (Iraq had weapons of mass destruction), 72% of Bush supporters believed this was true while 26% of Kerry supporters believed this statement (it is, of course, wrong). Since we're testing if both were equally misinformed, enter an expected frequency of 0.5 and 0.5 (or 1 to 1) in the expected frequency box.

Next, enter the observed percentages (72 and 26) and click the "Show Me!" button.

The Chi-square analysis is performed and gives a value of 21.591. This is significant at p<0.001. Thus, for this question, Bush supporters are significantly more misinformed than Kerry supporters.

It's also possible to input values such as 1 to 1 (instead of the frequencies 0.5 and 0.5). Here we analyze the question of "The Duelfer Report concluded that Iraq had WMD". This is clearly wrong and 56% of Bush supporters believed this to be the case while 18% of Kerry supporters thought this was true. Enter 56 and 18 into the calculator and click the "Show Me!" button.

The calculator shows that Bush supporters were significantly more confused about reality than Kerry supporters (Chi-square=19.513, p<0.001).