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. tab1=matrix(c(94,39, 120,89),nc=2) prop.test(tab1, correct=FALSE)

Gives something like this:

2-sample test for equality of proportions without continuity correction data: tab1 X-squared = 6.1026, df = 1, p-value = 0.01350 alternative hypothesis: two.sided 95 percent confidence interval: 0.03074072 0.23838896 sample estimates: prop 1 prop 2 0.4392523 0.3046875