نتایج جستجو برای: lognormal

تعداد نتایج: 2539  

2016
L. Clerkin D. Kirk M. Manera O. Lahav F. Abdalla A. Amara D. Bacon C. Chang E. Gaztañaga A. Hawken B. Jain B. Joachimi V. Vikram T. Abbott S. Allam R. Armstrong A. Benoit-Lévy G. M. Bernstein R. A. Bernstein E. Bertin D. Brooks D. L. Burke A. Carnero Rosell M. Carrasco Kind M. Crocce C. E. Cunha C. B. D’Andrea L. N. da Costa S. Desai H. T. Diehl J. P. Dietrich T. F. Eifler A. E. Evrard B. Flaugher P. Fosalba J. Frieman D. W. Gerdes D. Gruen R. A. Gruendl G. Gutierrez K. Honscheid D. J. James S. Kent K. Kuehn N. Kuropatkin M. Lima P. Melchior R. Miquel B. Nord A. A. Plazas A. K. Romer A. Roodman E. Sanchez M. Schubnell I. Sevilla-Noarbe R. C. Smith M. Soares-Santos F. Sobreira E. Suchyta M. E. C. Swanson G. Tarle A. R. Walker

It is well known that the probability distribution function (PDF) of galaxy density contrast is approximately lognormal; whether the PDF of mass fluctuations derived from weak lensing convergence (κWL) is lognormal is less well established. We derive PDFs of the galaxy and projected matter density distributions via the Counts in Cells (CiC) method. We use maps of galaxies and weak lensing conve...

Journal: :Suid-Afrikaanse Tydskrif vir Natuurwetenskap en Tegnologie 1989

Journal: :Proceedings of the American Mathematical Society 1994

2014
Søren Asmussen Jens Ledet Jensen Leonardo Rojas-Nandayapa

In this review, we will consider two closely related problems associated with the lognormal distribution: The approximation of the distribution of a lognormal sum (in the whole support) and the approximation of the Laplace transform of a lognormal distribution. The Laplace transform of the lognormal distribution can be employed to approximate the distribution of the lognormal sum via transform ...

2002
Robert Serfling

In parametric modeling of loss distributions in actuarial science, a versatile choice with intermediate tail weight is the lognormal distribution. Surprisingly, however, the fitting of this model using estimators which are at once efficient and robust has not been seriously addressed in the extensive literature. Consequently, for example, typical estimators of the lognormal mean and variance fa...

2017
Claudio Maccone

The discovery of new exoplanets makes us wonder where each new exoplanet stands along its way to develop life as we know it on Earth. Our Evo-SETI Theory is a mathematical way to face this problem. We describe cladistics and evolution by virtue of a few statistical equations based on lognormal probability density functions (pdf) in the time. We call b-lognormal a lognormal pdf starting at insta...

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...

Journal: :J. Informetrics 2016
Mike Thelwall

Although statistical models fit many citation data sets reasonably well with the best fitting models being the hooked power law and discretised lognormal distribution, the fits are rarely close. One possible reason is that there might be more uncited articles than would be predicted by any model if some articles are inherently uncitable. Using data from 23 different Scopus categories, this arti...

2000
A. Brodsky

A review of the author’s findings over four decades will show that the lognormal probability density function can be fit to many types of positive-variate radiation measurement and response data. The cumulative lognormal plot on probability vs. logarithmic coordinate graph paper can be shown to be useful in comparing trends in exposure distributions or responses under differing conditions or ex...

Journal: :Journal of Probability and Statistics 2013

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