G*Power (Erdfelder, Faul, & Buchner, 1996) was designed as a general stand-alone power analysis program for statistical tests commonly used in social and behavioral research. G*Power 3 is a major extension of, and improvement over, the previous versions. It runs on widely used computer platforms (i.e., Windows XP, Windows Vista, and Mac OS X 10.4) and covers many different statistical tests of thet, F, and χ2 test families. In addition, it includes power analyses forz tests and some exact tests. G*Power 3 provides improved effect size calculators and graphic options, supports both distribution-based and design-based input modes, and offers all types of power analyses in which users might be interested. Like its predecessors, G*Power 3 is free.

https://link.springer.com/content/pdf/10.3758/BF03193146.pdf

G*Power 3: A flexible statistical power analysis program for the social, behavioral, and biomedical sciences

THE DESIGN AND ANALYSIS OF EXPERIMENTS. By Oscar Kempthorne. New York, John Wiley and Sons, Inc., 1952. 631 pp. $8.50. This book by a teacher of statistics (as well as a consultant for \"experimenters\") is a comprehensive study of the philosophical background for the statistical design of experiment. It is necessary to have some facility with algebraic notation and manipulation to be able to use the volume intelligently. The problems are presented from the theoretical point of view, without such practical examples as would be helpful for those not acquainted with mathematics. The mathematical justification for the techniques is given. As a somewhat advanced treatment of the design and analysis of experiments, this volume will be interesting and helpful for many who approach statistics theoretically as well as practically. With emphasis on the \"why,\" and with description given broadly, the author relates the subject matter to the general theory of statistics and to the general problem of experimental inference. MARGARET J. ROBERTSON

The Design and Analysis of Experiments

1. Introduction and Overview. 2. Detecting Influential Observations and Outliers. 3. Detecting and Assessing Collinearity. 4. Applications and Remedies. 5. Research Issues and Directions for Extensions. Bibliography. Author Index. Subject Index.

Regression Diagnostics: Identifying Influential Data and Sources of Collinearity

This paper presents a review and critique of statistical null hypothesis testing in ecological studies in general, and wildlife studies in particular, and describes an alternative. Our review of Ecology and the Journal of Wildlife Management found the use of null hypothesis testing to be pervasive. The estimated number of P-values appearing within articles of Ecology exceeded 8,000 in 1991 and has exceeded 3,000 in each year since 1984, whereas the estimated number of P-values in the Journal of Wildlife Management exceeded 8,000 in 1997 and has exceeded 3,000 in each year since 1994. We estimated that 47% (SE = 3.9%) of the P-values in the Journal of Wildlife Management lacked estimates of means or effect sizes or even the sign of the difference in means or other parameters. We find that null hypothesis testing is uninformative when no estimates of means or effect size and their precision are given. Contrary to common dogma, tests of statistical null hypotheses have relatively little utility in science and are not a fundamental aspect of the scientific method. We recommend their use be reduced in favor of more informative approaches. Towards this objective, we describe a relatively new paradigm of data analysis based on Kullback-Leibler information. This paradigm is an extension of likelihood theory and, when used correctly, avoids many of the fundamental limitations and common misuses of null hypothesis testing. Information-theoretic methods focus on providing a strength of evidence for an a priori set of alternative hypotheses, rather than a statistical test of a null hypothesis. This paradigm allows the following types of evidence for the alternative hypotheses: the rank of each hypothesis, expressed as a model; an estimate of the formal likelihood of each model, given the data; a measure of precision that incorporates model selection uncertainty; and simple methods to allow the use of the set of alternative models in making, formal inference. We provide an example of the information-theoretic approach using data on the effect of lead on survival in spectacled eider ducks (Somateria fischeri). Regardless of the analysis paradigm used, we strongly recommend inferences based on a priori considerations be clearly separated from those resulting from some form of data dredging.

Null hypothesis testing: problems, prevalence, and an alternative

It is well known that statistical power calculations can be valuable in planning an experiment. There is also a large literature advocating that power calculations be made whenever one performs a statistical test of a hypothesis and one obtains a statistically nonsignificant result. Advocates of such post-experiment power calculations claim the calculations should be used to aid in the interpretation of the experimental results. This approach, which appears in various forms, is fundamentally flawed. We document that the problem is extensive and present arguments to demonstrate the flaw in the logic.

/pdf/the-abuse-of-power-the-pervasive-fallacy-of-power-2pgs8gsae8.pdf

The Abuse of Power: The Pervasive Fallacy of Power Calculations for Data Analysis

Characterizing vertical forest structure using small-footprint airborne LiDAR

Chitosan is a biopolymer that exhibits osteoconductive, enhanced wound healing and antimicrobial properties which make it attractive for use as a bioactive coating to improve osseointegration of orthopaedic and craniofacial implant devices. Coatings made from 91.2% de-acetylated chitosan were chemically bonded to titanium coupons via silane-glutaraldehyde molecules. The bond strength of the coatings was evaluated in mechanical tensile tests, and their dissolution and cyto-compatibility were evaluated in vitro using cell-culture medium and UMR 106 osteoblastic cells, respectively. The results showed that the chitosan coatings were chemically bonded to the titanium substrate and that the bond strengths (1.5-1.8 MPa) were not affected by gas sterilization. However, the chitosan bond strengths were less than those reported for calcium-phosphate coatings. The gas-sterilized coatings exhibited little dissolution over 8 weeks in cell-culture solution, and the attachment and growth of the UMR 106 osteoblast cells...

Chitosan: potential use as a bioactive coating for orthopaedic and craniofacial/dental implants.


A standardized descriptive language for Cheddar cheese flavor was developed and validated. Representative Cheddar cheeses (240) were collected. Fifteen individuals from industry, academia, and government participated in a 3-d roundtable discussion to generate descriptive flavor terms. A highly trained descriptive panel (n = 11) refined the terms and identified references. Cheddar cheeses (24) were presented to the panel for validation with the identified lexicon. The panel differentiated the 24 Cheddar cheeses as determined by univariate and multivariate analysis of variance (P < 0.05). Twenty-seven terms were identified to describe Cheddar flavor. Seventeen descriptive terms were present in most Cheddar cheeses. A standard sensory language for Cheddar cheese will facilitate training and communication between different research groups.

/pdf/development-of-a-descriptive-language-for-cheddar-cheese-4y7dku3xj5.pdf

Development of a Descriptive Language for Cheddar Cheese

Various metals are added to poultry diets to facilitate weight increase and disease prevention. The large amounts of poultry waste produced annually are dispersed intensively over relatively small areas of land, resulting in accumulations that pose potential environmental risks to the surface and groundwater. The focus of this study was to assess the distribution of heavy metals among various solid-phase fractions in soil profiles from a 25-year poultry waste-amended soil. Copper and Zn accumulated close to the soil surface where the total amounts of Cu and Zn in waste-amended soils were significantly higher than in nonamended soils. The total metal concentrations in amended soils were not critically high. Copper in the amended soil was present mostly in the organic matter (OM) fraction (46.9%), whereas Zn was found in the easily reducible oxide (ERO) fraction (47.3%). This suggests that the Cu and Zn in this long-term amended soil are potentially bioavailable and mobile. We observed the mobility of Zn through much of the soil profile of the long-term waste-amended soil. Zinc in this soil profile was found primarily in forms of the residual (RES) and crystalline iron oxide bound (CryFe) fractions, followed by the organic matter-bound and exchangeable (EXC) fractions.

Accumulation of heavy metals in a long-term poultry waste-amended soil

Power analysis after study completion has been suggested to interpret study results. We present 3 methods of estimating power and discuss their limitations. We use simulation studies to show that estimated power can be biased, extremely variable, and severely bounded. We endorse the practice of computing power to detect a biologically meaningful difference as a tool for study planning but suggest that calculation of confidence intervals on the parameter of interest is the appropriate way to gauge the strength and biological meaning of study results.

Patrick D. Gerard

Papers

Characterizing vertical forest structure using small-footprint airborne LiDAR

Chitosan: potential use as a bioactive coating for orthopaedic and craniofacial/dental implants.

Development of a Descriptive Language for Cheddar Cheese

Accumulation of heavy metals in a long-term poultry waste-amended soil

Limits of retrospective power analysis