نتایج جستجو برای: likelihood ratio test lrt

تعداد نتایج: 1327129  

2014
Madhusudan Bhandary Koji Fujiwara

An alternative test for the equality of several intraclass correlation coefficients under unequal family sizes based on several independent multinormal samples is proposed. It was found that the alternative test consistently and reliably produced results superior to those of Likelihood ratio test (LRT) proposed by Bhandary and Alam (2000) and max F test proposed by Bhandary and Fujiwara (2006) ...

Journal: :Systematic biology 2006
Maria Anisimova Olivier Gascuel

We revisit statistical tests for branches of evolutionary trees reconstructed upon molecular data. A new, fast, approximate likelihood-ratio test (aLRT) for branches is presented here as a competitive alternative to nonparametric bootstrap and Bayesian estimation of branch support. The aLRT is based on the idea of the conventional LRT, with the null hypothesis corresponding to the assumption th...

2006
Phillip W. Braddy Adam W. Meade Emily C. Johnson

Using male/female and Caucasian/African American comparison groups, this study examined the practical ramifications of using two IRT-based analytic methods, DFIT and the Likelihood Ratio Test (LRT), in assessing the measurement invariance of a 21-item leadership development scale under ten sample size conditions (e.g., 200, 500, & 1000). In nine of ten conditions, the LRT identified multiple it...

Journal: :Systematic biology 2005
Rafael Sanjuán Borys Wróbel

A variety of analytical methods is available for branch testing in distance-based phylogenies. However, these methods are rarely used, possibly because the estimation of some of their statistics, especially the covariances, is not always feasible. We show that these difficulties can be overcome if some simplifying assumptions are made, namely distance independence. The weighted least-squares li...

2009
Daniel R. JESKE Huaying Karen XU Todd BLESSINGER Peter JENSEN John TRUMBLE Daniel R. Jeske D. R. JESKE

The likelihood ratio test (LRT) for the equality of EC50 values using a probit model that has parallel slopes is implemented in a variety of software packages. A preliminary LRT can be used to ascertain the plausibility of parallel slopes. Testing for equal EC50 values is not as straightforward if the preliminary test rejects that the slopes are equal or, equivalently, if a practitioner would r...

2008
David A. van Dyk Alanna Connors Vinay L. Kashyap

The likelihood ratio test (LRT) and the related F test, popularized in astrophysics by Eadie et al. (1971), Bevington (1969), Lampton, Margon, and Bowyer (1976), Cash (1979), and Avni et al. (1978) do not (even asymptotically) adhere to their nominal χ and F distributions in many statistical tests common in astrophysics, thereby casting many marginal line or source detections and non-detections...

2013
Tiefeng Jiang Fan Yang

For random samples of size n obtained from p-variate normal distributions, we consider the classical likelihood ratio tests (LRT) for their means and covariance matrices in the high-dimensional setting. These test statistics have been extensively studied in multivariate analysis and their limiting distributions under the null hypothesis were proved to be chi-square distributions as n goes to in...

2009
Martina Chvosteková Viktor Witkovský

In this paper we present an exact likelihood ratio test (LRT) for testing the simple null hypothesis on all parameters of the linear regression model with normally distributed errors. In particular, we consider the simultaneous test for the regression parameters, β, and the error standard deviation, σ. The critical values of the LRT are presented for small sample sizes and a small number of exp...

Journal: :Biometrics 2011
Chong-Zhi Di Kung-Yee Liang

We consider likelihood ratio tests (LRT) and their modifications for homogeneity in admixture models. The admixture model is a two-component mixture model, where one component is indexed by an unknown parameter while the parameter value for the other component is known. This model is widely used in genetic linkage analysis under heterogeneity in which the kernel distribution is binomial. For su...

Journal: :EURASIP J. Information Security 2015
Tong Qiao Florent Retraint Rémi Cogranne Cathel Zitzmann

This paper investigates the statistical detection of JSteg steganography. The approach is based on a statistical model of discrete cosine transformation (DCT) coefficients challenging the usual assumption that among a subband all the coefficients are independent and identically distributed (i. i. d. ). The hidden information-detection problem is cast in the framework of hypothesis testing theor...

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