Testing environmental effects on taxonomic composition with canonical correspondence analysis: alternative permutation tests are not equal

Influence of Noisy Environmental Data on Canonical Correspondence Analysis

Canonical Correspondence Analysis (CCA) is an increasingly popular method for multivariate analysis of ecological community data. It is, however, one of the most potentially misleading multivariate methods for community analysis. Inclusion of noisy or irrelevant environmental variables can distort the representation of gradients in community structure. These hazards are illustrated with simulat...

Benthic Macroinvertabrate distribution in Tajan River Using Canonical Correspondence Analysis

The distribution of macroinvertebrate communities from 5 sampling sites of the Tajan River were used to examine the relationship among physiochemical parameters with macroinvertebrate communities and also to assess ecological classification system as a tool for the management and conservation purposes. The amount of variation explained in macroinvertebrate taxa composition is within values r...

Not all errors are created equal: metacognition and changing answers on multiple-choice tests.

Two experiments investigated the role of metacognition in changing answers to multiple-choice, general-knowledge questions. Both experiments revealed qualitatively different errors produced by speeded responding versus confusability amongst the alternatives; revision completely corrected the former, but had no effect on the latter. Experiment 2 also demonstrated that a pretest, designed to make...

All opinions are not equal.

To the Editor: Gibbons et al1 detail the “noble” and Herculean task of developing American College of Cardiology/American Heart Association cardiovascular guidelines. Recommendations are based on either experimental results or opinion, with the latter being considered of uniformly lower evidentiary importance. The contribution of opinion to the guidelines is substantial in that opinion supports...

Not All Effects Are Created Equal: A Rejoinder To Sawilowsky