A general class of dissimilarity measures among
k⩾2 distributions and their sample estimators are considered, for mixed continuous and categorical variables. The distributional properties are studied ...for the location model and the asymptotic distributions are investigated, in the general parametric case. The asymptotic distributions of the resulting statistics are used in various settings, to test statistical hypotheses.
Asymptotic distributions of the f-dissimilarity statistic, arising in the estimation of dissimilarity between populations, are investigated in a stratified random sampling set-up from the populations ...considered. Applications of these results in testing homogeneity of populations and equality of dissimilarities are discussed.
This chapter describes various adjustments that are needed for the traditional chi-square test statistics for goodness of fit, test of independency, and homogeneity for categorical data and analysis ...when data are obtained from complex survey designs.
L’objet de ce travail de thèse est le regroupement des essences bois du bassin du Congo en quatre groupes en fonction de la similitude de leurs propriétés mécaniques essentielles. Le module ...d’élasticité (MOE), propriété indicatrice, est estimé par une méthode non destructive : l’essai vibratoire. Pour chaque classe, le fractile à 5% d’exclusion supérieur d’une propriété mécanique est calculé à partir d’une théorie clairement exposée. Le bassin du Congo est un patrimoine en danger à cause des pressions anthropiques au premier rang desquelles figure la coupe hyper sélective des essences bois. Le résultat de ce regroupement permet de proposer comme substitut aux essences menacées d’extinction des essences aux propriétés mécaniques similaires plus disponibles en terme de ressources sur pied. D’où la contribution à la gestion durable et au maintien de la biodiversité du bassin du Congo. On montre que le MOE vibratoire est quasi-invariant avec la teneur en eau et qu’il est bien corrélé au MOE statique, à la masse volumique et à la contrainte à la rupture. C’est donc un bon prédicteur du module de rupture (MOR) à 12% du taux d’humidité du bois vert. Ceci valide l’organisation en groupe d’essences réalisée dans ce travail. Les valeurs caractéristiques des propriétés mesurées sont calculées pour chaque classe. Parce que l’Eurocode 5 exige que les bois utilisés en structure soient classés, nous proposons, in fine, un système de classement en structure des bois du bassin du Congo voué à une meilleure utilisation des forêts pour la conservation des écosystèmes forestiers et la satisfaction des besoins fondamentaux de l’homme.
This Ph.D. work deals with a non-destructive experimental approach organizing the species of the Congo basin in four groups according to the likeness of their main mechanical properties, and to guarantee for each group the 5th percentile characteristic value of mechanical properties such as the modulus of elasticity (MOE). For the sustainable management of forest and conservation of exotic biodiversity of the Congo basin, it is necessary to promote the exploitation of less-consumed species with equivalent mechanical characteristics. The aim of the present work is to propose a scheme for grouping species with similar values of modulus of elasticity (MOE) obtained through vibratory method. Only small clear specimens are tested. The assignment of a given specie to one of the four groups takes place in return for a homogeneity test of comparison of the random variables of species to the random variable of the group. Results of the present grading show that some species can be interchangeably consumed in the construction industry and that the procedure must include more species of the Congo basin. This property grouping will facilitate substitution of underutilized species for ones that are being more exploited. Thus, wood designers and constructors might have a wide variety of choices in their decision-making while promoting less-consumed species and reducing the demand of traditionally most wanted extinguishable species. The MOE obtained by intrinsic vibration of wood versus is not influenced by moisture content. So, the non destructive method bases on longitudinal vibrations can be used in industrial production of timber to certify the modulus of rupture (MOR) at 12% moisture content of green wood by direct correlation. Finally, we propose a grading system of tropical wood.
Exact Tests for Interaction in Several 2 × 2 Tables Hirji, Karim F.; Vollset, Stein E.; Reis, Isildinha M. ...
Journal of computational and graphical statistics,
09/1996, Volume:
5, Issue:
3
Journal Article
Peer reviewed
The investigation of interaction in a series of 2 × 2 tables is warranted in a variety of research endeavors. Though many large-sample approaches for such investigations are available, the exact ...analysis of the problem has been formulated for the probability statistic only. We present several alternative statistics applicable in this context. We also give an efficient polynomial multiplication algorithm to compute exact distributions and tail areas for the family of stratum-additive statistics. Besides the probability statistic, these include the score, likelihood ratio, and other statistics. In addition to comparing, in empirical terms, the diverse computational strategies for exact interaction analysis, we also explore the theoretical linkages between them. Data from published papers are used for illustration.
Toussaint (1974) introduced a divergence measure between s populations as a generalization of the J-divergence. The asymptotic distribution of Toussaint's measure is obtained when the parameters are ...substituted by their maximum likelihood estimators and the s probability density functions belong to the exponential farnily. A procedure to test statistical hypotheses about s populations is given These results can also be applied to multinomial populations.
A test of homogeneity is derived for testing the quality of the parameters in several independent nonlinear autoregressive processes. Also, the joint limit distribution of the least squares ...estimators of the parameters based on multiple observations from a threshold autoregressive process is derived when the number of replications of the realization increases and the number of time points remains fixed. The case when the number of time points increases is also considered.
A test of homogeneity of independent populations is introduced in terms of the φ-divergence. The asymptotic power of the test is determined for local and nonlocal alternative hypotheses. A power ...approximation is also proposed, based on a normalizing transformation of the test statistics for testing homogeneity. The behaviour of the proposed approximations of the power function is numerically compared. A new statistic is obtained and the respective test is more powerful, in some cases, than the existing tests for testing homogeneity of multinomial populations.
This paper presents categorical data that were gathered at two urban clinics and two suburban clinics of Johns Hopkins in an effort to identify characteristics of young female patients who ...successfully complete the three-injection sequence of the Gardasil quadrivalent human papillomavirus vaccine (HPV4). Available categorical correlates included patient age group, patient race, clinic location type, type of insurance provider, and clinic practice type. The data may be used to illustrate graphical display techniques and inference procedures for categorical data, as well as illuminate ways in which relationships between categorical variables may be hidden or behave differently than expected in the presence of confounding variables. The methods used to gather the data may also serve to illustrate the limitations of drawing conclusions from observational studies.
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