> prop.test(table(D2$SMOKE,D2$RACE),correct=FALSE) 2-sample test for equality of proportions without continuity correction data: table(D2$SMOKE, D2$RACE) X-squared = 23.26, df = 1, p-value = 1.415e-06 alternative hypothesis: two.sided 95 percent confidence interval: 0.1863890 0.3809326 sample estimates: prop 1: 0.7733333 prop 2: 0.4896725
prop2 are the probabilities of success for your 2 groups. the
p-value is less than one minus the level (95% or 0.95) of the confidence interval, which indicates the proportions of the characteristic studied are statistically significantly different in the 2 groups.
maybe you can have a look at this tutorial which show a complete example of such test.