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19872
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Subject: Agricultural Statistics and Informatics × Author: KAU × End date: 1987 × Start date: 1987 ×
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    ThesisItemOpen Access
    Pattern of occurrence of rainfall and estimation of rainfall probabilities in northern districts of Kerala
    (Department of Statistics, College of Veterinary and Animal Sciences, Mannuthy, 1987) Santhoh, K; KAU; Prabhakaran, P V
    A study was undertaken with a view to characterize the pattern of occurrence of rainfall and to estimate the rainfall probabilities and confidence limits at six reporting stations of the northern districts of Kerala viz, Kasaragod, Irikkur, Cannanore, Kozhikode, Quilandy and Mananthody, Daily rainfall data of the past 30 years were used to investigate the pattern of fortnightly and seasonal rainfall occurrence by fitting a first order Markov chain model to the sequence of wet and dry days. The rainfall probabilities and confidence limits were computed by fitting appropriate probability distributions to fortnightly rainfall amounts. The results of the analysis showed that at all the centres, there were more chances for a wet day to be preceded by a wet day than by a dryday. The maximum expected length of wet spell at different centres was observed during 12th to 14th fortnight of the year. The state occupation probability at equillibrium for a wet day was also foundmaximum during the same period. It could be seen that at all the centres, the likely commencement of southwest monsoon would be in the 11th fortnight. Suitable probability distributions from among normal, root normal, log normal and gamma distribution were selected and fitted to fortnightly amounts of rainfall. Rainfall probabilities of getting a fixed amount or less of rainfall wore worked out together with the 80% and 90% confidence limits of the mean fortnightly rainfall. The 3rd fortnight of the year all over the centres was found to be the driest fortnight and the 12th or 13th fortnight was found to be the wettest fortnight of the year.
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    ThesisItemOpen Access
    Optimum size of plots in cocoa (Theobroma cacoa L.) a multivariate case
    (Department of Statistics, College of Veterinary and Animal Sciences, Mannuthy, 1987) Sheela, M A; KAU; Gopinathan Unnithan, V K
    A procedure to determine optimum size of experimental units in the multivariate case was proposed. For the purpose, the matrix of relative dispersion was defined and its determinant was used as the measure of variation for comparison of plots of different sizes. This procedure was illustrated with the help of observations on three characters of 738 trees of 'Forastero1 variety of cocoa raised in the' KADP farm of the Kerala Agricultural University, Vellanikkara. Optimum plot size also was obtained in the univariate case. The following three different methods of plot formation were used in this investigation. Method I The whole set of trees were divided into compact blocks of different sizes and plots of one to fifteen trees were formed by combining adjacent trees in the field. Method II All trees were arranged in descending order of magnitude of trunk girth and of the canopy spread separately and were divided into blocks of required size. Plots of one to fifteen trees were formed by combining adjacent trees in the list in each block for each arrangement. Method III The trees were first arranged in descending order of magnitude of each character and they were divided into blocks of required size. Plots of different sizes were formed within each block by the following procedure, let there be 'nk* trees in a block. The nk trees were divided into 1 n 1 groups of 'It* trees each bearing continuous serial numbers * When 'n' is even, the 1st plot was formed by combining 1th tree from each of the first 'n/2* groups and (k-i+j)st tree from each of the remaining 'n/2' groups, where i=1,2,....n. When 'n1 is odd, ith plot was formed by combining the i^h tree from each of the first (J[n+iy2) groups and (k-i+fy9^ tree from each of the remaining [(n-lj/2) groups, whore 1=1,2, n. Of the three methods of plot formation Method III, which was proposed in this study was found to be superior to Methods I and II for experiments in established gardens and Method I for experiments for which fresh planting is required Optimum size of plots were al so determined by three different methods viz., (a) that which requires minimum experimental material for a specified precision (b) that which has maximum efficiency and (c) that for which the best fitting model has maximum curvature.