We show that the marginal semigroup of a binary graph model is normal if and only if the graph is free of K4 minors. The technique, based on the interplay of normality and the geometry of the marginal cone, has potential applications to other normality questions in algebraic statistics.

in the present study, five log-normal models, normal model (n), and two four- parameter models namely gompertz (g) and fredlund (fr) were tested on 71 psd data from 10 soil textural classes. the jaky (j) and fr models had the smallest and largest r2 values for all of the soils, respectively. the results of comparing the n and simple log-normal (sl) models showed that the accuracy of the n model...

We describe a class of algorithms for evaluating posterior moments certain Bayesian linear regression models with normal likelihood and prior on the coefficients. The proposed methods can be used hierarchical mixed effects partial pooling over one group predictors, as well random two groups predictors. demonstrate performance applications, involving U.S. opinion polls modeling COVID-19 outbreak...

abstract in recent years, many researchers have attempted to estimate the soil hydraulic functions (e.g. soil moisture characteristics curve, and hydraulic conductivity function) using particle-size distribution (psd) curve. in these studies, an accurate mathematical representation of psd is required for fitting the observed data. so far, some mathematical models were developed with different l...