A STUDY OF TWEEDIE FAMILY OF DISTRIBUTIONS FOR RAINFALL MODELLING
KrishiKosh
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Title |
A STUDY OF TWEEDIE FAMILY OF DISTRIBUTIONS FOR RAINFALL MODELLING
M.Sc. |
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Creator |
LALL, SHWETANK
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Contributor |
Ghosh, Himadri
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Subject |
marketing, precipitation, sampling, byproducts, paper, biological phenomena, vegetables, forecasting, self help, wells
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Description |
The present study deals with the investigation of behaviour of monthly rainfall data. There are many exact zeroes in the rainfall recording of a month over a period of years. Probability distributions currently in use are not able to combine the discrete aspect of getting an exact zero reading of rainfall in a month and the aspect of amount of rainfall in the same month. Compound Poisson Tweedie distribution, however provides a better way to combine both the aspects in one probability distribution. In this work the compound Poisson Tweedie distribution has been used to fit the monthly rainfall data by computing the estimates of its parameters. For the purpose of estimation of parameters of compound Poisson Tweedie distribution a new algorithm has been developed and used in this work. Another approach to model monthly rainfall is modified gamma distribution with singularity at zero. This is a three parameter mixture distribution which gives a probability mass to the occurrence of zero in a month and defines a conditional density for the amount of rainfall. The parameters are estimated by developing an algorithm. For testing the goodness of fit of the distributions Kolmogrov-Smirnov test is used. Since the test requires the complete continuity of the distributions in their domain, we computed the theoretical distribution function both the distribution by using trapezoidal rule of numerical integration. The test shows that both the distributions are good for fitting the monthly rainfall data. In this investigation bootstrap technique has been employed to know the distribution of Kolmogrov-Smirnov test statistic. The bootstrap technique provides the relative goodness of fit of the proposed distribution. Thus it can be concluded that the Tweedie family of distributions are good for fitting rainfall months with few or many zero readings |
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Date |
2016-03-10T17:02:23Z
2016-03-10T17:02:23Z 2013 |
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Type |
Thesis
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Identifier |
http://krishikosh.egranth.ac.in/handle/1/65054
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Language |
en_US
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Format |
application/pdf
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Publisher |
IARI, IASRI, NEW DELHI
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