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Record ID: 10 [ Page 16 of 16, No. 1 ]
Investigating the Efficiency of Stratified Ranked Set Sampling Using Nonparametric Bootstrap Estimation
Authors: Kevin Carl P. Santos; Jenniebie Salagubang
Abstract:
This paper aims to compare stratified random sampling and stratified ranked set sampling. A simulation study is conducted to evaluate the performance of the parameter estimates on both sampling techniques. Population sizes, sampling rates, stratum sizes, and correlation of the target variable and concomitant variable were varied, nonparametric bootstrap was then used in estimating the mean and its standard error. The coefficient of variation (CV) and the bias of the bootstrap estimates were compared. Stratified ranked set sampling generally outperforms stratified random sampling in terms of bias most especially for small populations. The two sampling designs were used in estimating the average mango production per barangay in the country.
Keywords: ranked set sampling; nonparametric bootstrap estimation; stratification; simple random sampling
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Year: 2011 Vol.: 60 No.: 1
Record ID: 9 [ Page 16 of 16, No. 2 ]
Nonparametric Model-Based Predictive Estimation in Survey Sampling
Authors: April Anne H. Kwong
Abstract:
A nonparametric model-based estimator of the population total is proposed. The sample data along with the auxiliary information are used in fitting a generalized additive model that is then used in reconstructing the unknown population. The estimates of the population parameters are computed from the predicted population values (for the unsampled part of the population) and the sample values. A simulation study designed to account for different association patterns between the target variable and the auxiliary variable, population size, and sample size was conducted to evaluate the proposed procedure. The method is robust to data-generating model form, population size, and sampling rate, and is generally superior to design-unbiased estimators.
Keywords: model-based estimation; predictive estimation; nonparametric regression; additive model
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Year: 2011 Vol.: 60 No.: 1
Record ID: 8 [ Page 16 of 16, No. 3 ]
Teaching of Statistical Consulting in the Philippines
Authors: Erniel B. Barrios
Abstract:
Teaching in a developing country is generally challenging due to the inadequate infrastructures in the development of teaching materials and the facilities in the delivery of such. The teacher has to be creative enough in developing cost-effective teaching materials, efficiently allocating the limited resources. Statistical consulting is generally taught using audio-visual infrastructure support. In the Philippines, it has to be taught through case studies, coaching and guided practice to complement the absence or inadequate audio-visual facilities. The methods are fairly adequate in imparting to the students the techniques and necessary skills in the practice of statistical consulting.
Keywords: statistical consulting; statistics education
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Year: 2010 Vol.: 59 No.: 1
Record ID: 7 [ Page 16 of 16, No. 4 ]
Teaching Experiments for a Course in Introductory Statistics
Authors: Josefina V. Almeda
Abstract:
Appreciation of college students on the statistical science relies to a large extent on how the introductory course is managed. Two groups of students (undergraduate statistics majors and non-statistics majors) were exposed to teaching an introductory course. Within each group, half is exposed to fun games intended as enrichment activities, the other half served as the control. Grades after one semester were analyzed and treatment effect is computed through Heckmans’ Selection Model. While the treatment (games) is beneficial for the non-statistics majors, it is disadvantageous for the statistics majors. For students with inherent interest in statistics, the introductory course will only require a clear presentation of concepts that will help them appreciate the discipline. However, the non-statistics majors or those with negative perception on statistics, fun activities like games can help conceal their dislike for statistical science and help improve the eventual outcomes in the course.
Keywords: fun games; Heckmans’ Selection Model; treatment effect
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Year: 2010 Vol.: 59 No.: 1
Record ID: 6 [ Page 16 of 16, No. 5 ]
The Random Component of the Levy Fractional Brownian Motion: A Rotation-Scale-Reflection-Invariant Random Field
Authors: Jeffry J. Tejada
Abstract:
This paper shows that the Levy fractional Brownian motion (LFBM) on the plane factors as a product of two components, one being a deterministic trend term and the other being a rotation-scale-reflection-invariant (RSRI) random field. An important consequence of this characterization is that one can study the LFBM by establishing the properties of the associated RSRI random field.
Keywords: Levy fractional Brownian motion; rotation-scale-reflection-invariant random field
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Year: 2010 Vol.: 59 No.: 1
Record ID: 5 [ Page 16 of 16, No. 6 ]
Backfitting Estimation of a Response Surface Model
Authors: Jhoanne Marsh C. Gatpatan
Abstract:
The backfitting algorithm is used in estimating a response surface model with covariates from a data generated through a central composite design. Backfitting takes advantage of the orthogonality generated by the central composite design on the design matrix. The simulation study shows that backfitting yield estimates and predictive ability of the model comparable to that from ordinary least squares when the response surface bias is minimal. Ordinary least squares estimates generally fails when the response surface bias is large, while backfitting exhibits robustness and still produces reasonable estimates and predictive ability of the fitted model. Orthogonality facilitates the viability of assumptions in an additive model where backfitting is an optimal estimation algorithm.
Keywords: backfitting; response surface model; second order model; central composite design
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Year: 2010 Vol.: 59 No.: 1
Record ID: 4 [ Page 16 of 16, No. 7 ]
Knowledge, Attitudes, and Practices of Filipino Households in Relation to Avian Influenza: A Pilot Study
Authors: Josefina V. Almeda; Jonathan G. Yabes
Abstract:
Avian influenza, commonly known as bird flu, once threatened the lives of birds as well as of human beings. Caused by a virus, it is considered endemic in many parts of Indonesia and Vietnam and in some parts of Cambodia, China, and Thailand. Outbreak of many similar diseases can easily reach epidemic level because households have minimal knowledge of precautionary measures. This study conducted a survey of Filipino households’ knowledge, attitudes, and practices related to avian influenza. Results of this assessment can help in the development of intervention strategies for the mitigation of the hazards such outbreaks may cause to humans. The results of the knowledge, attitudes, and practices study is beneficial to the country since it showed that there should be an improvement on the publics’ knowledge of transmission and preventive measure and that health professionals and other concerned agencies should provide effective information to prevent the disease.
Keywords: knowledge; attitudes; practices; avian influenza
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Year: 2010 Vol.: 59 No.: 1
Record ID: 3 [ Page 16 of 16, No. 8 ]
Loglinear and Classification Tree Models of the Decision Paradigm of the Tuberculosis Diagnostic Committee
Authors: Caryl Rose E. Alfonte
Abstract:
The TB Diagnostic Committees (TBDC) evaluate cases of pulmonary tuberculosis (PTB) symptomatics who are smear-negative, but whose chest x-rays show lesions suggestive of tuberculosis that may warrant anti-TB treatment. In a review of the 600 TBDC referral forms of new patients who consulted at Manila district health centers from 2006 to 2008, the demographic and clinical characteristics associated with a positive chest x-ray and eventually leading to a diagnosis of new active PTB are identified using loglinear models and classification trees.
Keywords: Classification tree, Loglinear model, Positive chest x-ray, Pulmonary tuberculosis, Sputum smear-negative, TB Diagnostic Committee
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Year: 2010 Vol.: 59 No.: 1
Record ID: 2 [ Page 16 of 16, No. 9 ]
Spatio-Temporal Modeling of Growth in Rice Production in the Philippines
Authors: Angela D. Nalica
Abstract:
When the strong El Nino episode in recent history happened in 1998, gross value added of the rice sector in the Philippines declined by as much as 24% while other crops were able to keep the decline to within single digit level. The convergence hypothesis was verified among the Philippine provinces with reference to rice production. Convergence could mean harmonized efforts among various stakeholders to increase production and hopefully aim for food sufficiency. Divergence on the other hand could imply the need for structural assessment of the sector including the goals of various stakeholders, so that an optimal strategy that can stimulate development will be identified. A spatial term is incorporated into the model, providing empirical evidence for the need to localize rice production policy programs across the country. The spatial term also accounts for the natural endowments of the producing provinces that complement those policies in realizing progress in the sector. Rice production among the Philippine provinces diverged in the period 1990-2002. The El Nino episode of 1998 pulled down rice yield by as much as 10% aggravating further the divergence among provinces.
Keywords: spatio-temporal model; backfitting; autoregression; convergence hypothesis; agricultural growth
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Year: 2010 Vol.: 59 No.: 1
Record ID: 1 [ Page 16 of 16, No. 10 ]
What Drives the Dynamic Conditional Correlation of Foreign Exchange and Equity Returns?
Authors: Gregorio A. Vargas
Abstract:
This paper establishes the link of microstructure and macroeconomic factors with the time-varying conditional correlation of foreign exchange and excess equity returns. By using the proposed DCC model with exogenous variables, capital flows and interest rate differentials are shown to be significant determinants of this correlation which is inclusive of the short-run variation of both asset returns. The results also provide evidence of the dynamic behavior of global investors as they seek parity in equity returns between home and foreign markets to reduce exchange rate risks.
Keywords: uncovered equity parity; order flow; DCCX
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Year: 2010 Vol.: 59 No.: 1