Twosample test for independent proportions
The application prop.test in R outputs the chi square statistic as the test statistic along with the confidence interval for the difference. The data should be provided as a matrix with 2 columns giving the counts of successes and failures, respectively.

Gives something like this:
2sample test for equality of proportions without continuity
correction
data: tab1
Xsquared = 6.1026, df = 1, pvalue = 0.01350
alternative hypothesis: two.sided
95 percent confidence interval:
0.03074072 0.23838896
sample estimates:
prop 1 prop 2
0.4392523 0.3046875

