Two-sample 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:
2-sample test for equality of proportions without continuity
X-squared = 6.1026, df = 1, p-value = 0.01350
alternative hypothesis: two.sided
95 percent confidence interval:
prop 1 prop 2