Virginia Institute of Marine Science
Environmental Toxicology And Chemistry
This critical review describes the confused application of significance tests in environmental toxicology and chemistry that often produces incorrect inferences and indefensible regulatory decisions. Following a brief review of statistical testing theory, nine recommendations are put forward. The first is that confidence intervals be used instead of hypothesis tests whenever possible. The remaining recommendations are relevant if hypothesis tests are used. They are as follows: Define and justify Type I and II error rates a priori; set and justify an effect size a priori; do not confuse p(E vertical bar H-0) and p(H-0 vertical bar E); design tests permitting Positive Predictive Value estimation; publish negative results; estimate a priori, not post hoe, power; as warranted by study goals, favor null hypotheses that are not conventional nil hypotheses; and avoid definitive inferences from isolated tests.
Confidence-Intervals; Published Research; Epidemiology; Probability; False; Power
Newman, MC, what exactly are you inferring? A closer look at hypothesis testing (2008). Environmental Toxicology And Chemistry, 27(5), 1013-1019.