Hi andye.

I'm not sure if you will derive significant benefit from my suggestion but I felt compelled to offer:

The OmegaHat Project

If you find that your data is not normally distributed, you could use a non-parametric test (e.g. Kruskal-Wallis, Wilcoxon Mann-Whitney, Kolmogorov-Smirnov, etc). Don't hesitate to ask for help with the statistical tests if the need arises.

Thanks,
Katie