The results obtained in the determination of mercury in solid wastes by AAS using two preparation methods1are compared through statistical parametric and non-parametric tests, linear regression and informational analysis of variance. The informational analysis of variance (IANOVA) method is a distribution-free procedure valid under minimal assumptions. It is not influenced by the range of the data and has very satisfactory robustness properties. Applying this algorithm to compare the effectiveness of the traditional water-bath digestion method with the microwave digestion method discussed in ref. 1, it was possible to assess the proportional errors introduced by microwave digestion method concerning the analysis of mercury in waste samples.