نتایج جستجو برای: normal distribution

تعداد نتایج: 1131872  

Journal: :Journal of Advanced Research 2010

2010
DUDLEY STARK D. Stark

The normal curve has been used to fit the rate of both world and US oil production. In this article we give the first theoretical basis for these curve fittings. It is well known that oil field sizes can be modeled by independent samples from a lognormal distribution. We show that when field sizes are lognormally distributed, the starting time of the production of a field is approximately a lin...

Journal: :Ecology 2009
Sean R Connolly Maria Dornelas David R Bellwood Terence P Hughes

Patterns in the commonness and rarity of species are a fundamental characteristic of ecological assemblages; however, testing between alternative models for such patterns remains an important challenge. Conventional approaches to fitting or testing species abundance models often assume that species, not individuals, are the units that are sampled and that species' abundances are independent of ...

2014
Meng Fei Wu Li-chun Zhang Jia-sheng Deng Guo-dong Ni Zhi-hui

In order to calculate the ground movement induced by displacement piles driven into horizontal layered strata, an axisymmetric model was built and then the vertical and horizontal ground movement functions were deduced using stochastic medium theory. Results show that the vertical ground movement obeys normal distribution function, while the horizontal ground movement is an exponential function...

2016
Kwasi A. Darkwah Ezekiel N. N. Nortey Anani Lotsi

The main objective of the study is to compare the Newton-Cotes methods such as the Trapezium rule, Simpson 1/3 rule and Simpson 3/8 rule to estimate the area under the Lorenz curve and Gini coefficient of income using polynomial function with degree 5. Comparing the Gini coefficients of income computed from the Polynomial function with degree 5 for the Trapezium, Simpson 1/3 and Simpson 3/8 met...

Journal: :International archives of occupational and environmental health 2013
G Truchon R Tardif G Charest-Tardif A de Batz P O Droz

PURPOSE Few studies compare the variabilities that characterize environmental (EM) and biological monitoring (BM) data. Indeed, comparing their respective variabilities can help to identify the best strategy for evaluating occupational exposure. The objective of this study is to quantify the biological variability associated with 18 bio-indicators currently used in work environments. METHOD I...

2007
Quang V. Cao Qinglin Wu

The length data from 12 samples of wood fibers and particles were described using lognormal and Weibull distributions. While both distributions fitted the middle range of the data well, the lognormal distribution provided a closer fit for short fibers and particles and the Weibull distribution was more appropriate for long ones. A mixture of the lognormal and Weibull distributions was developed...

Journal: :journal of sciences islamic republic of iran 0

consider an exchangeable normal vector with parameters ????2, and ?. on the basis of a vector observation some tests about these parameters are found and their properties are discussed. a simulation study for these tests and a few nonparametric tests are presented. some advantages and disadvantages of these tests are discussed and a few applications are given.

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه الزهراء - دانشکده علوم پایه 1391

چکیده بهبود برآوردگرهای پارامترهای جامعه مورد توجه برخی از آماردانان تحت شرایط متفاوت می باشد. در سالهای اخیر لاهیتران و ویجکون)2009) برآورد پارامترهای جامعه را زمانیکه اطلاعات اضافی در دسترس باشد بهبود دادند و روش تعمیم یافته ای را برای بدست آوردن برآوردگرهای انقباضی بهینه معرفی کردند. ما می خواهیم براساس قضایایی که لاهیتران و ویجکون مطرح کردند برآوردگرهای انقباضی را برای پارامترهای میانگی...

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