نتایج جستجو برای: lognormal distribution

تعداد نتایج: 609413  

Journal: :Journal of Modern Applied Statistical Methods 2016

2011
T. J. O. Afullo

A study of the raindrop size distribution along the eastern coast of South Africa (Durban) is presented. The Biweight kernel estimator based on distometer measurement is used to determine the best estimate of the measured raindrop size probability distribution function (pdf). The best kernel estimator, which results in the lowest integral square error (ISE), is used to measure the closeness of ...

In this paper, we consider admissible estimation of the parameter ?r in the gamma distribution with truncated parameter space under entropy loss function. We obtain the classes of admissible estimators. The result can be applied to estimation of parameters in the normal, lognormal, pareto, generalized gamma, generalized Laplace and other distributions.

Journal: :The Annals of occupational hygiene 2011
Kalimuthu Krishnamoorthy Zhao Xu

The problem of assessing occupational exposure using the mean or an upper percentile of a lognormal distribution is addressed. Inferential methods for constructing an upper confidence limit for an upper percentile of a lognormal distribution and for finding confidence intervals for a lognormal mean based on samples with multiple detection limits are proposed. The proposed methods are based on t...

2010
Igor Aurélio Silva Marcus Vinicius Cianciaruso Marco Antônio Batalha

(Abundance distribution of common and rare plant species of Brazilian savannas along a seasonality gradient). We examined the species abundance distribution (SAD) of plant communities in: (1) a wet grassland, waterlogged throughout most of the year; (2) a seasonal savanna, with an annual dry season; and (3) a hyperseasonal savanna, with alternating drought and waterlogging over the year. We sea...

2001
Srdjan S. BORJANOVIC Srdjan V. DJORDJEVIC

A Method for Evaluating Exposure to Nitrous Oxides by Application of Lognormal Distribution: S.S. BORJANOVIC, et al. Department of Work Physiology, Institute of Occupational Health “Dr Dragomir Karajovic”—A lognormal distribution adequately describes exposure to nitrous oxides in a work environment. The aim of this paper was to assign to the measured data a certain degree of variability which d...

Journal: :Journal of occupational and environmental hygiene 2006
K Krishnamoorthy Thomas Mathew Gurumurthy Ramachandran

The problem of assessing occupational exposure using the mean of a lognormal distribution is addressed. The novel concepts of generalized p-values and generalized confidence intervals are applied for testing hypotheses and computing confidence intervals for a lognormal mean. The proposed methods perform well, they are applicable to small sample sizes, and they are easy to implement. Power studi...

2012
ANDREW CHESHER

Precis: Lyons' (1972) data on the distribution of Irish wealth are considered and the appropriateness of the lognormal and Pareto models for this data are assessed using relatively sophisticated statistical methods. Allowance is made for the 65 per cent of individuals whose estate size is unrecorded. New estimates of total wealth and of the distribution of wealth in Ireland are obtained. Part o...

2002
Kabir K. Dutta David F. Babbel Franklin Allen Richard J. Herring

It has been observed that return distributions in general and interest rates in particular exhibit skewness and kurtosis that cannot be explained by the lognormal distribution commonly used as an assumption in many option pricing models. We have replaced the lognormal assumption in the Black (1976) model with the g-and-h distribution and derived a simple, closed-form option pricing formula unde...

Journal: :The Journal of neuroscience : the official journal of the Society for Neuroscience 2009
Alexei A Koulakov Tomás Hromádka Anthony M Zador

Two recent experimental observations pose a challenge to many cortical models. First, the activity in the auditory cortex is sparse, and firing rates can be described by a lognormal distribution. Second, the distribution of nonzero synaptic strengths between nearby cortical neurons can also be described by a lognormal distribution. Here we use a simple model of cortical activity to reconcile th...

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