Kenneth J. Berry

Multi-response permutation procedures for a priori classifications

An exact permutation test for analyzing and/or dredging multi-response data at the ordinal or higher levels is presented. The associated test statistic is based on the average distance (or any specified norm) between points within a priori disjoint subgroups of a finite population of points in an r-dimensional space (corresponding to r measured responses from each object in a finite population of objects). Alternative approximate tests based on the beta and normal distributions are provided. Two detailed examples utilizing actual social science data are considered, including comparisons of the approximate tests. An additional example describes the behavior of these tests under a variety of conditions, including extreme data configurations

Predicting Atlantic Basin Seasonal Tropical Cyclone Activity by 1 August

Abstract More than 90% of all seasonal Atlantic tropical cyclone activity typically occurs after 1 August. A strong predictive potential exists that allows seasonal forecasts of Atlantic basin tropical cyclone activity to be issued by 1 August, prior to the start of the active portion of the hurricane season. Predictors include June-July meteorological information of the stratospheric quasi-biennial oscillation (QBO), West African rainfall, the El Nino-Southern Oscillation (ENSO) as well as sea level pressure anomalies (SLPA), and the upper-tropospheric zonal-wind anomalies (ZWA) in the Caribbean basin. Use of a combination of these global and regional predictors provides a basis for making cross-validated (jackknifed) 1 August hindcasts of subsequent Atlantic seasonal tropical cyclone activity that show substantial skill over climatology. This relationship is demonstrated in 41 years of hindcasts of the 1950-90 seasons. It is possible to independently explain more than 60% of the year-to-year variability...

Predicting Atlantic Seasonal Hurricane Activity 6–11 Months in Advance

Abstract A surprisingly strong long-range predictive signal exists for Atlantic-basin seasonal tropical cyclone activity. This predictive skill is related to two measures of West African rainfall in the prior year and to the phase of the stratospheric quasi-biennial oscillation of zonal winds at 30 mb and 50 mb, extrapolated ten months into the future. These predictors, both of which are available by 1 December, can be utilized to make skillful forecasts of Atlantic tropical cyclone activity in the following June-November season. Using jackknife methods to provide independent testing of datasets, it is found that these parameters can be used to forecast nearly half of the season-to-season variability for seven indices of Atlantic seasonal tropical cyclone activity as early as late November of the previous year.

Data-dependent permutation techniques for the analysis of ecological data

Two distribution-free permutation techniques are described for the analysis of ecological data. These methods are completely data dependent and provide analyses for the commonly-encountered completely-randomized and randomized-block designs in a multivariate framework. Euclidean distance forms the basis of both techniques, providing consistency with the observed distribution of data in many ecological studies.

Application of Multi-Response Permutation Procedures for Examining Seasonal Changes in Monthly Mean Sea-Level Pressure Patterns

Abstract This paper considers the examination of possible differences in monthly sea-level pressure patterns, The satisfactory examination of such differences requires appropriate multi-response parametric methods based on unknown multivariate distributions (i.e., an appropriate parametric technique is probably non-existent). In order to avoid the likely insurmountable difficulties involving parametric methods, the application of multi-response permutation procedures (MRPP) is suggested as an appropriate approach for the examination of such differences.

A Generalization of Cohen's Kappa Agreement Measure to Interval Measurement and Multiple Raters:

Cohens kappa statistic is frequently used to measure agreement between two observers employing categorical polytomies. In this paper, Cohens statistic is shown to be inherently multivariate in nature; it is expanded to analyze ordinal and interval data; and it is extended to more than two observers. A nonasymptotic test of significance is provided for the generalized statistic.

An extended class of permutation techniques for matched pairs

A class of matched-pairs permutation techniques based on distances between each pair of observed signed values is considered. Although many commonly-used inference techniques for matched pairs are members of this class, some of the more appealing inference techniques among this class have received very little attention. Two new simple rank tests of this class jointly possess both intuitive properties and location-alternative power characteristics which appear more appealing than the corresponding characteristics of either the sign test or the Wllcoxon signed-ranks test. In particular, power comparisons based on slmula-tions indicate that these new rank tests are jointly as good or even vastly superior to the sign test or the Wilcoxon signed-ranks test for location alternatives involving five symmetric distributions. The five distributions selected for these com-parisons include the Laplace, logistic, normal, uniform and a U-shaped distribution

Long-Term Variations of Western Sahelian Monsoon Rainfall and Intense U.S. Landfalling Hurricanes

Abstract Western Sahelian rainfall during the primary rainy season of June through September is shown to he significantly associated with concurrent intense U.S. landfalling hurricanes during the last 92 years. The meet intense hurricanes (i.e., Saffir–Simpson Scale Category 3, 4, or 5) have an especially strong relationship with Sahelian rainfall, whereas weaker hurricanes show little or no association. The hurricane-Sahelian rainfall association is most evident along the U.S. East Coast but is negligible in the U.S. Gulf Coast region.

Children's blood lead and standardized test performance response as indicators of neurotoxicity in metropolitan New Orleans elementary schools

This study analyzes pre-Katrina variation in aggregate student performance and childrens blood lead (BPb) in 117 elementary school districts in metropolitan New Orleans. Fourth grade student achievement on Louisiana Educational Assessment Program (LEAP) tests were analyzed as a function of BPb for children 1-6 years old within school districts, controlling for student-teacher ratios, percent of students eligible for a free or discounted lunch, and school racial demography. Measures of performance across subject areas (English Language Arts, Science, Mathematics, and Social Studies) include school Achievement Test Scores (ATS) and indices of agreement and variation in student achievement. ATS are measured on a 5-point scale, corresponding to achievement categories of advanced=5 to unsatisfactory=1. Regression results show that median BPb (microg/dL) and percent of children with BPb > or =10 microg/dL are significantly associated with reductions in test scores across all subjects and depress variation in student performance across achievement categories. These data suggest that assisting children with improved school performance requires alleviation of pre-school Pb exposure and its associated neurotoxic damage. Cost-benefit calculations suggest that it is more cost effective to pay for onetime primary prevention instead of paying continuous expenses focused on reversing neurotoxic damage.

Improvements in the Permutation Test for the Spatial Analysis of the Distribution of Artifacts into Classes

Refinements and extensions to the permutation test for assessing the intrasite patterning of artifact distributions in an archaeological space are presented. Specifically, a Pearson type III distribution is employed to approximate the sampling distribution of the test statistic, an improved weighting is introduced to increase the efficiency of the test, and a method is presented to permit the inclusion of unclassified artifacts in the spatial analysis.