I have two large, non-normal samples as evidenced by the Kolmogorov-Smirnov test. I now wish to test for equality of variance nonparametrically. I'm confused as to which nonparametric test is appropriate when comparing variances across two samples that are both non-normal. I have seen Fligner-Killeen and Brown-Forsythe, though I'm not positive which option is best. The samples are not paired, and neither is normal. I'll be performing the test in R.