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This essay grew out of an examination of one-tailed significance testing. One-tailed tests were little advocated by the founders of modern statistics but are widely used and recommended nowadays in the biological, behavioral and social sciences. The high frequency of their use in ecology and animal behavior and their logical indefensibil-ity have been(More)
In artificial pools Gambusia affinis greatly reduced rotifer, crustacean, and insect populations and thus permitted extraordinary development of phytoplankton populations (2x10(8) cells per milliliter). Other effects included decreased optical transmissivity and increased temperature of the water, decreased amounts of dissolved inorganic phosphorus, and(More)
We examined the statistical analyses of experimental data in 95 papers published during 1966-1990 on the ecology, physiology, and behavior of freshwater invertebrate zooplankti-vores. Serious statistical errors were found in 51% of the papers. The frequencies of particular types of errors were as follows: sacrificial pseudoreplication (31%), simple(More)
The commentary by Tatarnikov (2005) on the design and analysis of manipulative experiments in ecology represents an obvious danger to readers with poor knowledge of modern statistics due to its erroneous interpretation of pseudoreplication and statistical independence. Here we offer clarification of those concepts--and related ones such as experimental unit(More)
The history, definitions, and transdisciplinary extent of pseudoreplication, as well as some key concepts of experimental design, are briefly reviewed. Pseudoreplication, sometimes also referred to as the 'unit of analysis error,' is one of the commonest errors of statistical analysis and interpretation. It is a simple albeit serious one. It persists in(More)
For those who have not recognized the disparate natures of tests of statistical hypotheses and tests of scientific hypotheses, one-tailed statistical tests of null hypotheses such as ∂ ≤ 0 or ∂ ≥ 0 have often seemed a reasonable procedure. We earlier reviewed the many grounds for not regarding them as such. To have at least some power for detection of(More)
One-tailed statistical tests are often used in ecology, animal behaviour and in most other fields in the biological and social sciences. Here we review the frequency of their use in the 1989 and 2005 volumes of two journals (Animal Behaviour and Oecologia), their advantages and disadvantages, the extensive erroneous advice on them in both older and modern(More)