Hello, I'm looking for some guidance with the following problem:
I've 2 samples A (111 items) and B (10 items) drawn from the same unknown population. Witihn A I find 9 "positives" and in B 0 positives. I'd like to know if the 2 samples A and B are different, ie is there a way to find out whether the number of "positives" is significantly different in A and B? I'm currently using prop.test, but unfortunately some of my data contains less than 5 items in a group (like in the example above), and the test statistics may not hold: > prop.test(c(9,0), c(111,10)) 2-sample test for equality of proportions with continuity correction data: c(9, 0) out of c(111, 10) X-squared = 0.0941, df = 1, p-value = 0.759 alternative hypothesis: two.sided 95 percent confidence interval: -0.02420252 0.18636468 sample estimates: prop 1 prop 2 0.08108108 0.00000000 Warning message: Chi-squared approximation may be incorrect in: prop.test(c(9, 0), c(111, 10)) Do you have suggestions for an alternative test? many thanks for your help, +kind regards, Arne ______________________________________________ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help