Skip to Main Content
Choosing a Transformation in Analyses of Insect Counts from Contagious Distributions with Low MeansAuthor(s): W.D. Pepper; S.J. Zarnoch; G.L. DeBarr; P. de Groot; C.D. Tangren
Source: Res. Pap. SRS-5.Asheville, NC: U.S. Department of Agriculture, Forest Service, Southern Research Station. 16 p.
Publication Series: Research Paper (RP)
Station: Southern Research Station
View PDF (1.4 MB)
DescriptionGuidelines based on computer simulation are suggested for choosing a transformation of insect counts from negative binomial distributions with low mean counts and high levels of contagion. Typical values and ranges of negative binomial model parameters were determined by fitting the model to data from 19 entomological field studies. Random sampling of negative binomial distributions was simulated and ANOVA’s were performed on simulated data for randomized complete block designs with treatment means corresponding to means of negative binomial distributions. The influence of analysis variable, treatment-mean configuration, range in treatment means, significance level of statistical tests, level of contagion, number of blocks, and number of replications in time on observed power and Type I error of F-tests was studied. A computer program was developed to recompute observed power of F-tests for any combination of these factors. The program facilitates choosing a transformation and may also be used to evaluate tradeoffs and determine affordable experimental factors for a future design with a given set of statistical attributes.
- You may send email to email@example.com to request a hard copy of this publication.
- (Please specify exactly which publication you are requesting and your mailing address.)
- We recommend that you also print this page and attach it to the printout of the article, to retain the full citation information.
- This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.
CitationPepper, W.D.; Zarnoch, S.J.; DeBarr, G.L.; de Groot, P.; Tangren, C.D. 1997. Choosing a Transformation in Analyses of Insect Counts from Contagious Distributions with Low Means. Res. Pap. SRS-5.Asheville, NC: U.S. Department of Agriculture, Forest Service, Southern Research Station. 16 p.
KeywordsContagious distribution, entomology, transformation, variance-mean relationship, variance stabilization.
- A Mixed-Effects Heterogeneous Negative Binomial Model for Postfire Conifer Regeneration in Northeastern California, USA
- Derivation of two well-behaved theoretical contagion indices and their sampling properties and application for assessing forest landscape diversity
- Logistic quantile regression provides improved estimates for bounded avian counts: a case study of California Spotted Owl fledgling production
XML: View XML