I have data showing fire fighter entrance exam results. I am testing the hypothesis that exam results and ethnicity are not mutually independent. To test this, I ran a Pearson chi-square test in R. The results show what I expected, but it gave a warning that "
In chisq.test(a) : Chi-squared approximation may be incorrect."
> a white black asian hispanic pass 5 2 2 0 noShow 0 1 0 0 fail 0 2 3 4 > chisq.test(a) Pearson's Chi-squared test data: a X-squared = 12.6667, df = 6, p-value = 0.04865 Warning message: In chisq.test(a) : Chi-squared approximation may be incorrect
Does anyone know why it gave a warning? Is it because I am using a wrong method?