Department of Quantitative Methods
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Item An observatory note on tests for normality assumptions(Journal of Modelling in Management, 2014) Ahmed F. SiddiqiPurpose – The purpose of this paper is to discuss how numerous tests that are available in statistical literature to assess normality of a given set of observations perform in normal and near-normal situations. Not all these tests are suitable for all situations but each test has an exclusive area of application. Design/methodology/approach – These tests are assessed for their power at varying degrees of skewness, kurtosis and sample size on the basis of simulated experiments. Findings – It is observed that almost all these tests are indifferent for smaller values of skewness and kurtosis. Further, the power of accepting normality reduces with increasing sample size. Originality/value – The article gives guidelines to researchers to apply normality assessing tests in different situations.Item A new class of generalized exponential ratio and product type estimators for population mean using variance of an auxiliary variable(Journal of Statistics, 2014) Hina Khan; Ahmad Faisal SiddiqiIn this paper, a general class of Estimator and Exponential Ratio and Product Type of Estimators for estimating finite population mean in Single Phase Sampling is considered. The expression for the Bias and Mean Square Error (MSE) of the first order approximation of the proposed class of Estimators are given. The properties of the proposed Estimators have been analyzed for independent units under Simple Random Sampling without replacement (SRSWOR) with ignoring finite population Correction Factor. It has been shown that the proposed Ratio and Product Exponential Type Estimators are more efficient than Simple Random Sampling, Classical Ratio and Bhal and Tuteja (1991) Estimator.