Statistical analysis of the effect of high dilutions of arsenic in a large dataset from a wheat germination model

This paper describes the statistical analysis of a series of experiments using a simple biological model (wheat germination in vitro), where a large number of wheat seeds were treated with homeopathic potencies of Arsenic trioxide. Some potencies, such as As 2O 3 40x, 42x and 45x, have repeatedly shown a significant stimulating effect on germination compared to controls, whereas As 2O 3 35x has a significant inhibiting effect. In some experiments the seeds were stressed before the experiment with a sublethal dose of the same substance. We performed a statistical analysis, both for stressed and non-stressed seed groups, using Poisson distribution as a suitable model for representing the number of non-germinated seeds in a standard experiment with 33 seeds in the same Petri dish. Finally, we have considered the most repeated potencies (30x and 45x), computing the sample odds ratio (OR) and a 95% confidence interval (CI) for the population OR. Our results show significant reproducible effects of some As 2O 3 decimal potencies, particularly As 2O 3 45x. In stressed seeds, even decimal potencies of water seem to give significant results compared to control, whereas high dilutions of As 2O 3 without potentization never show significant effects.