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Mathematical methods and statistical distributions present exact results in the climate calculations and hydrological processes. Awareness of the rainfall probability distribution provides the appropriate conditions for water resource planning. Many studies have been done to estimate probability of rainfall by various methods due to the importance of rainfall distribution in the economic, social and particularly agriculture studies. In these studies, the various probabilistic models have been used and the results of the most investigations show that the bivariate gamma distribution branches of gamma model are compatible for rainfall data. The bivariate gamma distribution is used in the hydrological processes modeling. In the present paper, supposing that the X and Y follow the crovelli’s bivariate gamma model, at first a brief description was given in the case of the exact distributions of the functions U=X+Y, P=XY and Q=X⁄((X+Y)) as well as their respective moments, then the validity of this model was evaluated for Rasht airport weather station data. The results showed that rainfall data of this region also confirms The suitability of the crovelli’s bivariate gamma model.

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In this paper, after stating the characteristicof some of continuous distributions including, gamma, Crovelli’s
gamma, Rayleigh, Weibull, Pareto, exponential and generalized gamma distribution with each other,these distributions
were fit on drought data of Guilan state and the best distribution was presented. Then, severity and duration of
the drought of different sites were investigated using standardized precipitation index.

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‎In this paper‎, ‎first‎, ‎we investigate probability density function and the failure rate function of some families of exponential distributions‎. ‎Then we present their features such as expectation‎, ‎variance‎, ‎moments and maximum likelihood estimation and we identify the most flexible distributions according to the figure of probability density function and the failure rate function and finally we offer practical examples of them‎.  

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‎In this paper‎, ‎a new distribution is introduced‎, ‎which is a generalization of a well-known distribution‎. ‎This distribution is flexible and applies to income data modeling‎. ‎We first provide some of the mathematical and distributional properties of this new model and then‎, ‎to demonstrate the flexibility the new distribution‎, ‎we will present the applications of this distribution with real data‎. ‎Data fitting results confirm the appropriateness of this new model for the real data set‎.

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Anthropometr is a science that deals with the size of the body including the dimensions of different parts, the field of motion and the strength of the muscles of the body. Specific individual dimensions such as heights, widths, depths, distances, environments and curvatures are usually measured. In this article, we investigate the anthropometric characteristics of patients with chronic diseases (diabetes, hypertension, cardiovascular disease, heart attacks and strokes) and find the factors affecting these diseases and the extent of the impact of each to make the necessary planning.

This research is done descriptively-analytically, the research community of the people of Ravansar county is one of the functions of Kermanshah province. MATLAB, R and SPSS statistical software are used to analyze the data and test the presented hypotheses. Significance level for all tests is less than 0.05. Descriptive statistics methods is used to describe and summarize the variables. The Pearson correlation analysis method is used to investigate the relationship between variables, regression analysis (logistics) is used to investigate the effect of independent variables on the dependent variable. According to the results, it seems that some anthropometric indicators have a significant relationship with risk factors of chronic diseases. So, continuous evaluations, lifestyle changes and increasing the level of awareness to control, prevent and adjust the indicators are suggested.