43 research outputs found
HIV Spread: Some Statistical Results
nc complexes of the formulae ZnX2L·nH2O [X = Cl or Br, n = 2, X = I, n = 1, L = L1, 1,3‐bis(benzimidazol‐2‐yl)benzene; X = Cl, Br or I, n = 0, L = L2, 1,3‐bis(1‐methylbenzimidazol‐2‐yl)benzene] and Zn(L)2(ClO4)2·2H2O (L = L1 and L2) were obtained by the reactions of zinc halides/perchlorate with N‐heterocycles in ethanol. The complexes have been characterized based on elemental analyses, molar conductance measurements, IR, 1H and 13C NMR spectral studies and thermal analysis
Location-shifts for improved estimation under Midzuno-Sen sampling scheme
Simple location-shifts for the study or auxiliary character are proposed under Midzuno-Sen sampling from a finite population. These aim at improving the efficiency of the classical Horvitz-Thompson estimator or the unbiased ratio estimator of a population total. It is demonstrated that the choice of the translation parameters is flexible. A few methods for assessing these parameters are outlined. The gain in efficiency of estimation is illustrated. © 2002 Elsevier Science B.V. All rights reserved
A generalization of midzuno-sen sampling scheme for finite populations
This paper proposes a generalization of the classical Midzuno-Sen sampling procedure to allow more than one PPSWOR selection followed by SRSWOR draws. The Horvitz-Thompson (H-T) estimator, its variance and variance estimator are discussed. Two methods of controlling the sampling variability of the H-T estimator are outlined. These require simple transformations of the study or the auxiliary variates. They can also be viewed as attempts to make the sampling scheme IPPS. Simple numerical illustrations are given
CONTRIBUTIONS TO SAMPLING THEORY AND PRACTICE USING AUXILIARY INFORMATION (INDIA).
Part One (Chapters 2-7) of the thesis illustrates mainly the use of auxiliary information in effecting certain transformations for improving the design/estimation strategies in sample surveys. A new product-type estimator which is complementary to the usual ratio estimator, in a certain sense, is proposed in Chapter 2. A transformation which permits the use of the product method in place of the more commonly used ratio method is discussed in the next chapter. One resulting convenience is that the bias and mean squared error of the estimator have closed form expressions, unlike that for the ratio estimator. Chapter 4 develops a change of origin for the study variate in order to improve the precision of the estimates under varying probability sampling. A change of origin under ratio method of estimation and a change of scale under the difference method are also examined. Raj (1965) has proposed a two-phase pps selection scheme in the absence of information on the auxiliary variate, but when information on some other variate is available. This also requires the knowledge of a certain parameter. Chapter 5 suggests an alternative two-phase procedure not requiring the knowledge of this parameter. Auxiliary variates in surveys are occasionally positive and negative valued. This introduces difficulties in ratio and product methods of estimation and in pps sampling. Chapter 6 outlines two simple methods of dealing with the situation: stratification by sign of the auxiliary variate and transformation by simple translation. For the purposes of illustration simple random sampling without replacement and probability proportional to size sampling with replacement are assumed. Finally, the scope for some future work is indicated in Chapter 7. Part Two (Chapters 8-9) of the thesis is a brief report on a sample survey conducted during 1980-81 to assess the transition of rural people to modern ways of life in the Karnataka State in South India.Dept. of Mathematics and Statistics. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis1982 .S724. Source: Dissertation Abstracts International, Volume: 43-07, Section: B, page: 2235. Thesis (Ph.D.)--University of Windsor (Canada), 1982
Application of Statistical Sampling to Audit and Control
The traditional literature applying statistical sampling to auditing sometimes overlooks the special structure of audit populations. Much of the literature is based on techniques developed for sample surveys. Of late there is an increasing awareness to take note of the unique environment in which audit sampling takes place and to incorporate all available auxiliary information to improve the precision of estimators. The present paper begins with a brief historical review and then focuses on the special nature of audit populations. This is followed by the description of a class of auxiliary information estimators and the occasional problem caused by situations of low frequency of errors but with large magnitudes. Next, monetary unit sampling is reviewed and key unit sampling is proposed as an alternative when the former may not apply. An outline of a Bayesian formulation to use prior information is provided. Finally, guidelines are provided for a choice of procedure enumerating the major factors to be considered
Interchangeability Of The Ratio And Product Methods In Sample Surveys
The paper demonstrates the interchangeability of the ratio and product methods of estimation in sample surveys through translating the unbiased estimator of the population total of the auxiliary variate (or the study variate). The values of the translation parameters minimizing the mean squared error are obtained. The allowable departures from this optimum, which still ensure a reduction in the mean squared error, as compared to the traditional case, are indicated. © 1983, Taylor & Francis Group, LLC. All rights reserved
Contributions to sampling theory and practice using auxiliary information
ThesisThesis, University of Windsor, 198
Judicial Approach towards Corruption in India: An Analysis
he traditional literature applying statistical sampling to auditing sometimes overlooks the special structure of audit populations. Much of the literature is based on techniques developed for sample surveys. Of late there is an increasing awareness to take note of the unique environment in which audit sampling takes place and to incorporate all available auxiliary information to improve the precision of estimators. The present paper begins with a brief historical review and then focuses on the special nature of audit populations. This is followed by the description of a class of auxiliary information estimators and the occasional problem caused by situations of low frequency of errors but with large magnitudes. Next, monetary unit sampling is reviewed and key unit sampling is proposed as an alternative when the former may not apply. An outline of a Bayesian formulation to use prior information is provided. Finally, guidelines are provided for a choice of procedure enumerating the major factors to be considered