Página 1 dos resultados de 732 itens digitais encontrados em 0.016 segundos

- INTERCIENCIA; CARACAS
- Biblioteca Digitais de Teses e Dissertações da USP
- Wiley-Blackwell
- Universidade Estadual Paulista
- Em: Conference Proceedings of 18th International Conference on Forecasting Financial Markets: Advances for Exchange Rates, Interest Rates and Asset Management (CD-ROM)
- Universidade Federal do Rio Grande do Norte; BR; UFRN; Programa de Pós-Graduação em Ciência e Engenharia de Materiais; Processamento de Materiais a partir do Pó; Polímeros e Compósitos; Processamento de Materiais a part
- Wayne State Univ Press
- BioMed Central Ltd
- Universidade Cornell
- Mais Publicadores...

## STATISTICAL TEST FOR GENOTYPE AND ENVIRONMENT CONTRIBUTION IN THE GENOTYPES x ENVIRONMENTS INTERACTION MATRIX

Fonte: INTERCIENCIA; CARACAS
Publicador: INTERCIENCIA; CARACAS

Tipo: Artigo de Revista Científica

ENG

Relevância na Pesquisa

65.98%

#GENOTYPE AND ENVIRONMENT CONTRIBUTION#GXE INTERACTION#NONCENTRAL CHI-SQUARE DISTRIBUTION#MODIFIED F TEST#MODELS#ECOLOGY

The objective of the present work was to propose a method for testing the contribution of each level of the factors in a genotypes x environments (GxE) interaction using multi-environment trials analyses by means of an F test. The study evaluated a data set, with twenty genotypes and thirty-four environments, in a block design with four replications. The sum of squares within rows (genotypes) and columns (environments) of the GxE matrix was simulated, generating 10000 experiments to verify the empirical distribution. Results indicate a noncentral chi-square distribution for rows and columns of the GxE interaction matrix, which was also verified by the Kolmogorov-Smirnov test and Q-Q plot. Application of the F test identified the genotypes and environments that contributed the most to the GxE interaction. In this way, geneticists can select good genotypes in their studies.; Conselho Nacional Cientifico e Tecnologico (CNPq); Brazilian science funding agencies; Brazilian science funding agencies; CNPq

Link permanente para citações:

## Redução no vício da distribuição da deviance para dados de contagem.; Bias reduction in the distribution of the deviance for count data.

Fonte: Biblioteca Digitais de Teses e Dissertações da USP
Publicador: Biblioteca Digitais de Teses e Dissertações da USP

Tipo: Dissertação de Mestrado
Formato: application/pdf

Publicado em 26/10/2001
PT

Relevância na Pesquisa

56.05%

Dados de contagem podem ser considerados, em geral, como provenientes de uma distribuição de Poisson. Neste contexto, a análise de tais dados apresenta certas dificuldades, pois não segue algumas pressuposições básicas para o ajuste de um modelo matemático. Desse modo, algumas transformações são sugeridas, mas nem sempre bons resultados são obtidos. No enfoque de Modelos Lineares Generalizados, a estatística que mede a qualidade do ajuste do modelo para os dados é chamada deviance. Porém, a distribuição da deviance é, em geral, desconhecida. No entanto, para dados com distribuição de Poisson, pode-se mostrar que a distribuição da deviance se aproxima de uma distribuição ?2, mas tal aproximação não é boa para tamanhos pequenos de amostra. Para melhorar essa aproximação, alguns fatores de correção para os dados são sugeridos, mas os resultados obtidos ainda não são satisfatórios. Assim, o objetivo deste trabalho é propor um novo fator de correção para os dados seguindo uma distribuição de Poisson, de modo a se obter uma melhora na distribuição da deviance para qualquer tamanho de amostra. Para isto, será adicionada uma constante à variável resposta e, através do valor esperado da deviance...

Link permanente para citações:

## An adaptive chart for monitoring the process mean and variance

Fonte: Wiley-Blackwell
Publicador: Wiley-Blackwell

Tipo: Artigo de Revista Científica
Formato: 821-831

ENG

Relevância na Pesquisa

55.88%

#Shewhart charts#AATS#adaptive charts#non-central chi-square distribution#single charts to#control the process mean and variance#joint (X)over-bar and R charts

Traditionally, an (X) over bar chart is used to control the process mean and an R chart is used to control the process variance. However, these charts are not sensitive to small changes in the process parameters. The adaptive ($) over bar and R charts might be considered if the aim is to detect small disturbances. Due to the statistical character of the joint (X) over bar and R charts with fixed or adaptive parameters, they are not reliable in identifing the nature of the disturbance, whether it is one that shifts the process mean, increases the process variance, or leads to a combination of both effects. In practice, the speed with which the control charts detect process changes may be more important than their ability in identifying the nature of the change. Under these circumstances, it seems to be advantageous to consider a single chart, based on only one statistic, to simultaneously monitor the process mean and variance. In this paper, we propose the adaptive non-central chi-square statistic chart. This new chart is more effective than the adaptive (X) over bar and R charts in detecting disturbances that shift the process mean, increase the process variance, or lead to a combination of both effects. Copyright (c) 2006 John Wiley & Sons...

Link permanente para citações:

## Influence of dental care for infants on caries prevalence: A comparative study

Fonte: Universidade Estadual Paulista
Publicador: Universidade Estadual Paulista

Tipo: Artigo de Revista Científica
Formato: 120-123

ENG

Relevância na Pesquisa

56.05%

#Caries prevalence#Dental caries#Infant oral health#chi square distribution#child#comparative study#controlled study#dental care#dental caries#dentin#enamel

Purpose: The influence of early dental care on the prevalence of dental caries was determined in children ages 35 to 40 months divided into 2 groups of 160 children each, with 1 group participating in a dental care program from the first year of life to the time of the study, while the other group did not receive any dental care. Methods: The clinical conditions considered for the evaluation were: sound teeth, enamel caries without cavitation, enamel caries with cavitation, and dentinal caries. The proportion and chi-square tests were used for statistical analysis with the level of significance set at 5%. Results: A significant difference regarding the presence of dental caries, especially in the number of children presenting enamel caries with cavitation (P<.0001), was observed between the 2 groups. The number of children with enamel caries without cavitation and dentinal caries was similar for the 2 groups. Conclusions: Considering the aspect of dental caries prevention, the authors concluded that children in the age range of 3 to 4 years who received early dental care showed better oral conditions.

Link permanente para citações:

## The no-central chi-square chart with two-stage samplings

Fonte: Universidade Estadual Paulista
Publicador: Universidade Estadual Paulista

Tipo: Conferência ou Objeto de Conferência
Formato: 9

ENG

Relevância na Pesquisa

76.22%

#Parameter estimation#Probability#Sampling#Statistical process control#Non-central chi-square chart#Graph theory

Throughout this article, it is assumed that the no-central chi-square chart with two stage samplings (TSS Chisquare chart) is employed to monitor a process where the observations from the quality characteristic of interest X are independent and identically normally distributed with mean μ and variance σ2. The process is considered to start with the mean and the variance on target (μ = μ0; σ2 = σ0 2), but at some random time in the future an assignable cause shifts the mean from μ0 to μ1 = μ0 ± δσ0, δ >0 and/or increases the variance from σ0 2 to σ1 2 = γ2σ0 2, γ > 1. Before the assignable cause occurrence, the process is considered to be in a state of statistical control (defined by the in-control state). Similar to the Shewhart charts, samples of size n 0+ 1 are taken from the process at regular time intervals. The samplings are performed in two stages. At the first stage, the first item of the i-th sample is inspected. If its X value, say Xil, is close to the target value (|Xil-μ0|< w0σ 0, w0>0), then the sampling is interrupted. Otherwise, at the second stage, the remaining n0 items are inspected and the following statistic is computed. Wt = Σj=2n 0+1(Xij - μ0 + ξiσ 0)2 i = 1,2 Let d be a positive constant then ξ...

Link permanente para citações:

## Divine proportions and facial esthetics after manipulation of frontal photographs.

Fonte: Universidade Estadual Paulista
Publicador: Universidade Estadual Paulista

Tipo: Artigo de Revista Científica
Formato: 103-108

ENG

Relevância na Pesquisa

56.05%

#cephalometry#chi square distribution#esthetics#face#female#histology#human#image processing#male#methodology#photography

AIM: To investigate the relationship between divine proportion and facial esthetics in frontal photographs as well as whether any of the 4 ratios for manipulation provide more favorable facial esthetics. MATERIAL AND METHODS: The sample comprised 20 frontal photographs of Caucasian individuals (11 males and 9 females). The photographs were digitized and stored on a compact disk. A photometric analysis was created with 7 facial segments that were measured on Image Tool software and 4 ratios between 2 facial segments calculated using Microsoft Excel. This manipulation led to 5 different photographs of the same individual: one photograph with no manipulation and the others with 1 of the ratios manipulated in the Deformer 2.0 to very close or equal to 1.618. Thereafter, the 5 photographs of all individuals were evaluated by 12 examiners. The examiners selected those photographs that were esthetically more pleasant. CONCLUSION: After evaluation, a chi-square test revealed a relationship between divine proportion and facial esthetics. Among the ratios selected, R1 and R2 provided more favorable facial esthetics.

Link permanente para citações:

## Influence of TNF-α blockers on the oral prevalence of opportunistic microorganisms in ankylosing spondylitis patients

Fonte: Universidade Estadual Paulista
Publicador: Universidade Estadual Paulista

Tipo: Artigo de Revista Científica
Formato: 679-685

ENG

Relevância na Pesquisa

55.88%

#Ankylosing spondylitis#Candida#Infection#Oral microbiology#Staphylococcus#Super-infection#TNF-α blockers#amoxicillin#amphotericin B#ampicillin#antibiotic agent

Objectives: To compare the oral prevalence and antimicrobial susceptibility of Candida spp., staphylococci, enterobacteriaceae, and pseudomonas spp.from ankylosing spondylitis (AS) patients receiving conventional and anti-TNF-α therapy. Methods: The study included 70 AS patients, diagnosed according to the modified New York criteria (1984). The volunteers were divided into 2 groups: a biological group (AS BioG) (n=35) (on anti-TNF-α therapy) and a conventional group (AS ConvG) (n=35). The control group (ContG) (n=70) was made up of healthy individuals matched for age, gender, and oral conditions. After clinical examination, oral rinse samples were collected and plated in specific culture media. The number of colony-forming units per milliliter (cfu/ml) was obtained, and isolates were identified using the API system. Antimicrobial susceptibility tests were performed according to the NCCLS guidelines. Prevalence and counts of microorganisms were statistically compared between the 3 groups, using the Mann-Whitney and Chi-square tests. Significance level was set at 5%. Results: In both the AS BioG and the AS ConvG, staphylococci counts were higher than that in the ContG (p<0.0001). Candida albicans and staphylococcus epidermidis were the most commonly found species in all the groups. Serratia marcescens and klebsiella oxytoca were more prevalent in the AS BioG and the AS ConvG...

Link permanente para citações:

## Speed and Accuracy Comparison of Noncentral Chi-Square Distribution Methods for Option Pricing and Hedging under the CEV Model

Fonte: Em: Conference Proceedings of 18th International Conference on Forecasting Financial Markets: Advances for Exchange Rates, Interest Rates and Asset Management (CD-ROM)
Publicador: Em: Conference Proceedings of 18th International Conference on Forecasting Financial Markets: Advances for Exchange Rates, Interest Rates and Asset Management (CD-ROM)

Tipo: Artigo de Revista Científica

POR

Relevância na Pesquisa

96.08%

Pricing options and evaluating greeks under the constant elasticity of variance (CEV) model require the computation of the noncentral chi-square distribution function. In this article, we compare the performance in terms of accuracy and computational time of alternative methods for computing such probability distributions against an xternally tested benchmark. In addition, we present closed-form solutions for computing greek measures under the CEV option pricing model for both beta < 2 and beta > 2, thus being able to accommodate direct leverage effects as well as inverse leverage effects that are frequently observed in the options markets.

Link permanente para citações:

## Detection of inbreeding effects by the chi-square test on genotypic and phenotypic frequencies.

Fonte: PubMed
Publicador: PubMed

Tipo: Artigo de Revista Científica

Publicado em /09/1980
EN

Relevância na Pesquisa

55.98%

The problem of detection of inbreeding effects by the chi-square goodness-of-fit test is investigated. The noncentrality parameter of the limiting chi-square distribution is considered as a function of the inbreeding coefficient in two models: (1) a gene locus with m codominant alleles and (2) the generalized ABO model. Previous results by Ward and Sing and by Chakraborty and Rao were based on inadequate statistical reasoning. In the first model, the resulting noncentrality parameter is identical with that found by Ward and Sing. For the second model, the limiting noncentrality parameter is found to be zero.

Link permanente para citações:

## Implementação da rotina de unfolding para determinação de distribuição de tamanho de grãos esféricos via distribuição de interceptos lineares e de área de seção

Fonte: Universidade Federal do Rio Grande do Norte; BR; UFRN; Programa de Pós-Graduação em Ciência e Engenharia de Materiais; Processamento de Materiais a partir do Pó; Polímeros e Compósitos; Processamento de Materiais a part
Publicador: Universidade Federal do Rio Grande do Norte; BR; UFRN; Programa de Pós-Graduação em Ciência e Engenharia de Materiais; Processamento de Materiais a partir do Pó; Polímeros e Compósitos; Processamento de Materiais a part

Tipo: Dissertação
Formato: application/pdf

POR

Relevância na Pesquisa

46.18%

#Esferas#Estereologia#Grão#Minimização do chi-quadrado#Simulação#Unfolding#Spheres#Stereology#Grains#Inimizes the chi-square#Simulation

Na unfolding method of linear intercept distributions and secction área distribution was implemented for structures with spherical grains. Although the unfolding routine depends on the grain shape, structures with spheroidal grains can also be treated by this routine. Grains of non-spheroidal shape can be treated only as approximation. A software was developed with two parts. The first part calculates the probability matrix. The second part uses this matrix and minimizes the chi-square. The results are presented with any number of size classes as required. The probability matrix was determined by means of the linear intercept and section area distributions created by computer simulation. Using curve fittings the probability matrix for spheres of any sizes could be determined. Two kinds of
tests were carried out to prove the efficiency of the Technique. The theoretical tests represent ideal cases. The software was able to exactly find the proposed grain size
distribution. In the second test, a structure was simulated in computer and images of its slices were used to produce the corresponding linear intercept the section area distributions. These distributions were then unfolded. This test simulates better reality. The results show deviations from the real size distribution. This deviations are caused by statistic fluctuation. The unfolding of the linear intercept distribution works perfectly...

Link permanente para citações:

## Phylogenetic relationships of human populations in sub-Saharan Africa

Fonte: Wayne State Univ Press
Publicador: Wayne State Univ Press

Tipo: Artigo de Revista Científica

Publicado em //2000
EN

Relevância na Pesquisa

55.88%

#Humans#Factor Analysis, Statistical#Immunoglobulin Gm Allotypes#Chi-Square Distribution#Phylogeny#Gene Frequency#Gene Pool#Haplotypes#Phenotype#Ethnic Groups#Immunoglobulin Km Allotypes

This study utilizes the GM/KM immunoglobulin allotype system to elucidate the phylogenetic relationships of sub-Saharan Africans. The importance of understanding the relatedness of these peoples stems from the sub-Saharan region being the possible birthplace of humans. Haplotype distributions were determined for 19 populations and compared using chi-square analysis. Published data of other sub-Saharan Africans and representative populations worldwide were also added for comparison. Genetic distances between populations were calculated based on haplotype frequencies, and genetic relationships were observed through principal components analysis. Data from the GM/KM system showed a genetic homogeneity of the Bantu populations, with some exceptions, supporting the possibility of a common origin of these peoples. The Malagasy appeared as a divergent population, most likely due to Southeast Asian/Austronesian admixture, as indicated by the presence of the GM*AF B haplotype. The Cape Coloured also showed a divergence, with their genetic structures containing Caucasoid and Khoisan contributions. Finally, the Mbuti Pygmies appeared genetically isolated and had the highest frequency of the GM*A B haplotype out of all studied populations.

Link permanente para citações:

## Protocol for population testing of an Internet-based Personalised Decision Support system for colorectal cancer screening

Fonte: BioMed Central Ltd
Publicador: BioMed Central Ltd

Tipo: Artigo de Revista Científica

Publicado em //2010
EN

Relevância na Pesquisa

55.88%

#Humans#Colorectal Neoplasms#Mass Screening#Linear Models#Chi-Square Distribution#Follow-Up Studies#Sample Size#Patient Selection#Internet#Decision Support Systems, Clinical#Middle Aged

Background: Australia has a comparatively high incidence of colorectal (bowel) cancer; however, population screening uptake using faecal occult blood test (FOBT) remains low. This study will determine the impact on screening participation of a novel, Internet-based Personalised Decision Support (PDS) package. The PDS is designed to measure attitudes and cognitive concerns and provide people with individually tailored information, in real time, that will assist them with making a decision to screen. The hypothesis is that exposure to (tailored) PDS will result in greater participation in screening than participation following exposure to non-tailored PDS or resulting from the current non-tailored, paper-based approach. Methods/design: A randomised parallel trial comprising three arms will be conducted. Men and women aged 50-74 years (N = 3240) will be recruited. They must have access to the Internet; have not had an FOBT within the previous 12 months, or sigmoidoscopy or colonoscopy within the previous 5 years; have had no clinical diagnosis of bowel cancer. Groups 1 and 2 (PDS arms) will access a website and complete a baseline survey measuring decision-to-screen stage, attitudes and cognitive concerns and will receive immediate feedback; Group 1 will receive information 'tailored' to their responses in the baseline survey and group 2 will received 'non-tailored' bowel cancer information. Respondents in both groups will subsequently receive an FOBT kit. Group 3 (usual practice arm) will complete a paper-based version of the baseline survey and respondents will subsequently receive 'non-tailored' paper-based bowel cancer information with accompanying FOBT kit. Following despatch of FOBTs...

Link permanente para citações:

## Chi-square approximation by Stein's method with application to Pearson's statistic

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Publicado em 07/07/2015

Relevância na Pesquisa

56.05%

This paper concerns the development of Stein's method for chi-square
approximation and its application to problems in statistics. New bounds for the
derivatives of the solution of the gamma Stein equation are obtained. These
bounds involve both the shape parameter and the order of the derivative.
Subsequently Stein's method for chi-square approximation is applied to bound
the distributional distance between Pearson's statistic and its limiting
chi-square distribution, measured using smooth test functions. In combination
with the use of symmetry arguments, Stein' method yields explicit bounds on
this distributional distance of order $n^{-1}$.; Comment: 32 pages

Link permanente para citações:

## Parameter Estimation in Astronomy with Poisson-Distributed Data. I. The Chi-Square-Gamma Statistic

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Publicado em 05/03/1999

Relevância na Pesquisa

46.25%

Applying the standard weighted mean formula, [sum_i {n_i sigma^{-2}_i}] /
[sum_i {sigma^{-2}_i}], to determine the weighted mean of data, n_i, drawn from
a Poisson distribution, will, on average, underestimate the true mean by ~1 for
all true mean values larger than ~3 when the common assumption is made that the
error of the ith observation is sigma_i = max(sqrt{n_i},1). This small, but
statistically significant offset, explains the long-known observation that
chi-square minimization techniques which use the modified Neyman's chi-square
statistic, chi^2_{N} equiv sum_i (n_i-y_i)^2 / max(n_i,1), to compare
Poisson-distributed data with model values, y_i, will typically predict a total
number of counts that underestimates the true total by about 1 count per bin.
Based on my finding that the weighted mean of data drawn from a Poisson
distribution can be determined using the formula [sum_i [n_i + min(n_i,1)]
(n_i+1)^{-1}] / [sum_i (n_i+1)^{-1}], I propose that a new chi-square
statistic, chi^2_gamma equiv sum_i [n_i + min(n_i,1) - y_i]^2 / [n_i + 1],
should always be used to analyze Poisson-distributed data in preference to the
modified Neyman's chi-square statistic. I demonstrate the power and usefulness
of chi-square-gamma minimization by using two statistical fitting techniques
and five chi-square statistics to analyze simulated X-ray power-law 15-channel
spectra with large and small counts per bin. I show that chi-square-gamma
minimization with the Levenberg-Marquardt or Powell's method can produce
excellent results (mean slope errors <=3%) with spectra having as few as 25
total counts.; Comment: 22 pages (LaTeX+aaspp4.sty)...

Link permanente para citações:

## Parameter Estimation in Astronomy with Poisson-Distributed Data. II. The Modified Chi-Square-Gamma Statistic

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Publicado em 21/07/2000

Relevância na Pesquisa

56.19%

I investigate the use of Pearson's chi-square statistic, the Maximum
Likelihood Ratio statistic for Poisson distributions, and the chi-square-gamma
statistic (Mighell 1999, ApJ, 518, 380) for the determination of the
goodness-of-fit between theoretical models and low-count Poisson-distributed
data. I demonstrate that these statistics should not be used to determine the
goodness-of-fit with data values of 10 or less. I modify the chi-square-gamma
statistic for the purpose of improving its goodness-of-fit performance. I
demonstrate that the modified chi-square-gamma statistic performs (nearly) like
an ideal chi-square statistic for the determination of goodness-of-fit with
low-count data. On average, for correct (true) models, the mean value of
modified chi-square-gamma statistic is equal to the number of degrees of
freedom (nu) and its variance is 2*nu --- like the chi-square distribution for
nu degrees of freedom. Probabilities for modified chi-square-gamma
goodness-of-fit values can be calculated with the incomplete gamma function. I
give a practical demonstration showing how the modified chi-square-gamma
statistic can be used in experimental astrophysics by analyzing simulated X-ray
observations of a weak point source (signal-to-noise ratio of 5.2; 40 photons
spread over 317 pixels) on a noisy background (0.06 photons per pixel).
Accurate estimates (95% confidence intervals/limits) of the location and
intensity of the X-ray point source are determined.; Comment: 40 pages (LaTeX+aaspp4.sty+flushrt.sty)...

Link permanente para citações:

## Chi-square Intervals for a Poisson Parameter - Bayes, Classical and Structural

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Publicado em 03/02/2011

Relevância na Pesquisa

56.05%

The 'standard' confidence interval for a Poisson parameter is only one of a
number of estimation intervals based on the chi-square distribution that may be
used in the estimation of the mean or mean rate for a Poisson model. Other
chi-square intervals are available for experimenters using Bayesian or
structural inference methods. Exploring these intervals also leads to other
alternate approximate chi-square intervals. Although coverage probability may
not always be of interest for Bayesian or structural intervals, coverage
probabilities are useful for validating 'objective' priors. Coverage
probabilities are explored for all of the intervals considered.; Comment: 14 pages

Link permanente para citações:

## Chi-square simulation of the CIR process and the Heston model

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Relevância na Pesquisa

56.22%

#Quantitative Finance - Computational Finance#Mathematics - Numerical Analysis#Mathematics - Probability#Mathematics - Statistics Theory#Quantitative Finance - Pricing of Securities#60H10, 60H35, 93E20, 91G20

The transition probability of a Cox-Ingersoll-Ross process can be represented
by a non-central chi-square density. First we prove a new representation for
the central chi-square density based on sums of powers of generalized Gaussian
random variables. Second we prove Marsaglia's polar method extends to this
distribution, providing a simple, exact, robust and efficient
acceptance-rejection method for generalized Gaussian sampling and thus central
chi-square sampling. Third we derive a simple, high-accuracy, robust and
efficient direct inversion method for generalized Gaussian sampling based on
the Beasley-Springer-Moro method. Indeed the accuracy of the approximation to
the inverse cumulative distribution function is to the tenth decimal place. We
then apply our methods to non-central chi-square variance sampling in the
Heston model. We focus on the case when the number of degrees of freedom is
small and the zero boundary is attracting and attainable, typical in foreign
exchange markets. Using the additivity property of the chi-square distribution,
our methods apply in all parameter regimes.; Comment: 32 pages, 6 figures, 8 tables, update

Link permanente para citações:

## Moments of the log non-central chi-square distribution

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Publicado em 21/03/2015

Relevância na Pesquisa

66.05%

The cumulants and moments of the log of the non-central chi-square
distribution are derived. For example, the expected log of a chi-square random
variable with v degrees of freedom is log(2) + psi(v/2). Applications to
modeling probability distributions are discussed.; Comment: 8 pages

Link permanente para citações:

## Information Divergence is more chi squared distributed than the chi squared statistics

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Relevância na Pesquisa

46.23%

For testing goodness of fit it is very popular to use either the chi square
statistic or G statistics (information divergence). Asymptotically both are chi
square distributed so an obvious question is which of the two statistics that
has a distribution that is closest to the chi square distribution.
Surprisingly, when there is only one degree of freedom it seems like the
distribution of information divergence is much better approximated by a chi
square distribution than the chi square statistic. For random variables we
introduce a new transformation that transform several important distributions
into new random variables that are almost Gaussian. For the binomial
distributions and the Poisson distributions we formulate a general conjecture
about how close their transform are to the Gaussian. The conjecture is proved
for Poisson distributions.; Comment: 5 pages, accepted for presentation at ISIT 2012

Link permanente para citações:

## On the computation of moments of the partial non-central chi-squared distribution function

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Publicado em 07/06/2013

Relevância na Pesquisa

55.85%

#Mathematics - Classical Analysis and ODEs#Mathematics - Probability#Mathematics - Statistics Theory#65D20

Properties satisfied by the moments of the partial non-central chi-square
distribution function, also known as Nuttall Q-functions, and methods for
computing these moments are discussed in this paper. The Nuttall Q-function is
involved in the study of a variety of problems in different fields, as for
example digital communications.; Comment: 6 pages

Link permanente para citações: