Mann-Whitney's test: use the Mann-Whitney's test to determine if the samples come from a single population or from two different populations. XLSTAT can perform a two-tailed or a one-tailed test. Note: the Mann-Whitney statistic is related to the Wilcoxon statistic, as the (unsigned) Wilcoxon test is equivalent to the Mann-Whitney test.
Kolmogorov-Smirnov's test: use the Kolmogorov-Smirnov's test to determine if the populations from which the samples were taken have different cumulative distribution functions. XLSTAT performs a two-tailed test.