Equivalence tests can enhance environmental science and management

Tests of point hypotheses are common in observational environmental studies, but there is concern about their appropriateness. Exhortations to restrict sample sizes on the basis of a power analysis for such tests may fail to satisfy the environmental professional, because sample sizes are not always easily controlled. Testing of interval hypotheses via equivalence test procedures offers a way of testing meaningful hypotheses and of giving effect to the precautionary principle. An example is given which concerns mining impacts on stream benthic invertebrate communities, and includes calculation of Bayesian posterior probabilities.