نتایج جستجو برای: lognormal

تعداد نتایج: 2539  

Journal: :Statistical methods in medical research 2002
K N Berk P A Lachenbruch

Consider repeated measures data with many zeros. For the case with one grouping factor and one repeated measure, we examine several models, assuming that the nonzero data are roughly lognormal. One of the simplest approaches is to model the zeros as left-censored observations from the lognormal distribution. A random effect is assumed for subjects. The censored model makes a strong assumption a...

Journal: :Bioinformatics 2009
Chuan Lu Ross D. King

MOTIVATION Distribution analysis is one of the most basic forms of statistical analysis. Thanks to improved analytical methods, accurate and extensive quantitative measurements can now be made of the mRNA, protein and metabolite from biological systems. Here, we report a large-scale analysis of the population abundance distributions of the transcriptomes, proteomes and metabolomes from varied b...

2009
Ralph Stern

Risk stratification is most directly and informatively summarized as a risk distribution curve. From this curve the ROC curve, predictiveness curve, and other curves depicting risk stratification can be derived, demonstrating that they present similar information. A mathematical expression for the ROC curve AUC is derived which clarifies how this measure of discrimination quantifies the overlap...

Journal: :The Journal of Economic Inequality 2007

Journal: :journal of research in health sciences 0
mina hoseini abbas bahrampour moghaddameh mirzaee

background: breast cancer is the most common cancer after lung cancer and the second cause of death. in this study we compared weibull and lognormal cure models with cox regression on the survival of breast cancer. study design: a cohort study. methods: the current study retrospective cohort study was conducted on 140 patients referred to ali ibn abitaleb hospital, rafsanjan southeastern iran f...

Journal: :iranian journal of earth science 0
shahrokh paravarzar department of mining and metallurgical engineering, amirkabir university of technology, 1359767191 tehran, iran nasser madani advance mining technology center (amtc), santiago, chile abbas maghsoudi department of mining and metallurgical engineering, amirkabir university of technology, tehran, iran peyman afza department of mining engineering, faculty of engineering, south tehran branch, islamic azad university, tehran, iran

estimation of gold reserves and resources has been of interest to mining engineers and geologists for ages. the existence of outlier values shows the economic part of the deposits subject to the fact that don’t depend on the human or technical errors. the presence of these high values causes a pseudo dramatically increment in variance estimation of economical blocks when applying conventional m...

2003
Iver H. Cairns

The variability of the Vela pulsar (PSR B0833-45) corresponds to well-defined field statistics that vary with pulsar phase, ranging from Gaussian intensity statistics offpulse to approximately power-law statistics in a transition region and then lognormal statistics on-pulse, excluding giant micropulses. These data are analyzed here in terms of two superposed wave populations, using a new calcu...

Journal: :international journal of business and development studies 0

empirical studies have shown that the size distribution of firms can be described as a lognormal or pareto distribution. however, these studies have focused on developed countries and little attention has been devoted to developing countries. using the variable of number of employees as a measure of firm size, this paper investigates the shape of firm size distribution in the food & beverages i...

2017
Romain Allez Rémi Rhodes Vincent Vargas

In this article, we consider the continuous analog of the celebrated Mandelbrot star equation with lognormal weights. Mandelbrot introduced this equation to characterize the law of multiplicative cascades. We show existence and uniqueness of measures satisfying the aforementioned continuous equation; these measures fall under the scope of the Gaussian multiplicative chaos theory developed by J....

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