Statistical Science Research Articles

Preface

The 2023 International Conference on Applied Mathematics and Digital Simulation (AMDS 2023) was held successfully on 28-29 December 2023 in Beijing, China. The contributions are the results of submissions from the conference participants, who provide readers with a broader view of mathematical, statistical and computational science methods, ideas and tools.There are 92 participants in AMDS 2023, in which the program includes 6 keynote reports (35-45 minutes), 48 oral presentations (15 mins+3 Q&A) included in four sessions (Mathematics and Computational Theory, Mathematical Modelling and Machine Learning Methods Statistics Modelling and Data Analysis, and Fluid Dynamics and Mechanics), 15 E-posts and 23 listeners. The point of the conference emphasizes the development of theories and applications and promotes interdisciplinary endeavors among mathematicians, statisticians, scientists, engineers and researchers from other related disciplines.This volume comprises selected papers from the AMDS2023 conference. Accepted manuscripts were peer-reviewed by 2 to 4 reviewers in a double-blind review process. A total of 48 reviewers participated in this conference and provided their professional comments to authors to ensure the quality of the manuscripts. There are six topic partitions, including Mathematics and Computational Theory, Statistics Modelling and Data Analysis, Mathematical Modelling and Machine Learning Methods, Fluid Dynamics and Mechanics, Mathematical Modelling in Physics and Control and Automation, which constitutes an up-to-date account of principles, techniques, and tools for mathematical simulation and modelling in a wide range of research fields.We would like to thank the authors of all papers and participants; the members of the Scientific Committee who assisted with the review of the papers submitted and presented at the conference; the four session chairs: Prof. Yichuan Zhao, Prof. Quanxin Zhu, Prof. P.M. Siva Raja, Prof. Rao Li; the six keynote speakers: Prof. Alexander G. Ramm, Prof. Ovidiu Radulescu, Prof. Hajime Urakawa, Prof. Yanjun Liu, Prof. Grienggrai Rajchakit and Prof. Oscar Eduardo Ruiz Salguero; the organzier and sponsors: the Hubei Mengshun Exhibition Service Center, the Research Center for Stochastic Configuration Machines (SCM), the National Laboratory for Scientific Computing (LNCC); the publisher: IOP Publishing Ltd agrees to publish the AMDS 2023 proceedings. We are grateful for your attendance and contribution to a successful AMDS 2023.Organizing Cmmittee of AMDS 2023Jiang Zhu (Advisory Chair)National Laboratory for Scientific Computing-LNCC, BraziList of Conference Committees are available in this Pdf.

Osnovni zavdannia ta predmet viiskovo-ekonomichnoi statystyky

The main tasks and subject of military-economic statistics as a branch of statistical discipline are proposed. The main challenges and tasks of the national economic system in the conditions of a full-scale military invasion of the Russian Federation into Ukraine are characterized, as the solution which will accelerate Ukraine’s victory in the war. Emphasis is placed on the importance of the following elements of statistical management support, such as accounting, analysis, and forecasting of the vector of development, taking into account all the burdens of war. The key role in this process should be given to the state administration, including state statistics bodies, and, accordingly, to the improvement of statistical literacy at the appropriate level of competence of specialists. Definitions of such concepts as: «military economy», «economic statistics of the Armed Forces», «economic statistics», and «military-economic statistics» are given, and they are also classified and structured among themselves. It was determined that military-economic statistics is a branch of statistical science that studies the quantitative side of mass military-economic phenomena and processes in an inextricable connection with their qualitative characteristics in the conditions of a certain place and time. The subject of the study of military-economic statistics is the quantitative side of mass military-economic phenomena and processes inextricably linked with their qualitative characteristics in the conditions of a certain place and time. Accordingly, the object of the study of military-economic statistics is the quantitative side of mass military-economic phenomena and processes. The structure of this branch of statistical science can be successfully presented in the educational process of higher education institutions for students studying economic and military specialties and specializations (general and special).

A Clinicopathological Study of Aural Polyps: A Retrospective Analysis in a Tertiary Care Hospital

Abstract Aim To document the varied clinical presentations and diagnosis of aural polyps Study Design Observational retrospective study. Introduction Aural polyps are a misnomer. Any lesion can present as a mass in the external auditory canal. Aural polyps are proliferation of the granulation tissue due to long standing inflammatory process with associated otalgia and otorrhea. Objectives To document the clinicoradiological presentations, intraoperative findings, and histopathological diagnosis of aural polyp, correlating them. Methods In our study 81 patients underwent treatment for aural polyps in the department of Ear, Nose, and Throat (ENT) from April 1997 to April 2022. Results were tabulated, a simple descriptive analysis was done using the Statistical Package Social Sciences software, and the results obtained were represented as percentages and presented in tables. Results The majority (38) of the patients presenting with aural polyps were diagnosed with mucosal and squamous type of CSOM, and 22 with simple granulation polyps. There were also 5 patients with malignant otitis externa, 3 patients had glomus tumors, 2 patients with retained foreign bodies, and 3 patients with brain herniation. We also identified aberrant internal carotid artery, high jugular bulb, one patient had facial nerve neuroma, one patient had polyp from the tragus diagnosed with tuberculosis, one patient with keratosis obturans, and one with exostosis. Conclusion A thorough detailed examination and mastoid exploration with radiological and histopathological evaluation is mandatory for better defining the definitive treatment. Utmost care and meticulousness are advised for the surgeons while dealing with aural polyps to avoid any complications.

Computer Algebra in R Bridges a Gap Between Symbolic Mathematics and Data in the Teaching of Statistics and Data Science

Computer Algebra in R Bridges a Gap Between Symbolic Mathematics and Data in the Teaching of Statistics and Data Science

Updated core competencies in pharmacoepidemiology to inform contemporary curricula and training for academia, government, and industry.

The first paper to specify the core content of pharmacoepidemiology as a profession was published by an ISPE (International Society for Pharmacoepidemiology) workgroup in 2012 (Jones JK et al. PDS 2012; 21[7]:677-689). Due to the broader and evolving scope of pharmacoepidemiology, ISPE considers it important to proactively identify, update and expand the list of core competencies to inform curricula of education programs; thus, better positioning pharmacoepidemiologists across academic, government (including regulatory), and industry positions. The aim of this project was to update the list of core competencies in pharmacoepidemiology. To ensure applicability of findings to multiple areas, a working group was established consisting of ISPE members with positions in academia, industry, government, and other settings. All competencies outlined by Jones et al. were extracted from the initial manuscript and presented to the working group for review. Expert-based judgments were collated and used to identify consensus. It was noted that some competencies could contribute to multiple groups and could be directly or indirectly related to a group. Five core domains were proposed: (1) Epidemiology, (2) Clinical Pharmacology, (3) Regulatory Science, (4) Statistics and data science, and (5) Communication and other professional skills. In total, 55 individual competencies were proposed, of which 25 were new competencies. No competencies from the original work were dropped but aggregation or amendments were made where considered necessary. While many core competencies in pharmacoepidemiology have remained the same over the past 10 years, there have also been several updates to reflect new and emerging concepts in the field.

Study of Covariates’ Effects in the Presence of Neighbor Effects : An Informative Review

With reference to a Gauss-Markov Model, Analysis of Covariance (ANCOVA) is a standard exercise in the study of differential treatment effects in the presence of covariates. Again in the presence of ‘Neighbor Effects’, we carry out necessary data analysis in a routine manner. In this paper we present a review of this area of research, encompassing both covariates’ effects and neighbor effects.  International Journal of Statistical Sciences, Vol.24(1), March, 2024, pp 65-73

Optimum Designs for Optimum Mixtures: An Informative Review

In a mixture experiment, the measured response is assumed to depend only on the relative proportions of ingredients or components present in the mixture. Scheffe´ (1958) first systematically considered this problem, and introduced different models and suitable designs. Optimum designs for the estimation of parameters in various mixture models are available in the literature. However, in a mixture experiment, interest is likely to be more on the optimum mixing proportions of the ingredients being used. In this exposition, we take the readers on a journey through the optimum designs developed for estimating the optimum mixture combination as accurately as possible under various mixture models. International Journal of Statistical Sciences, Vol.24(1), March, 2024, pp 1-14

New Series of D-efficient Covariate Designs under BIBD set-up

In the present study, an effort has been made to construct D-efficient covariate designs in BIB design (v, b, r, k and λ) set-up when either one of k and r is odd or both k and r are odd numbers and Hadamard matrix of order k i.e., Hk does not exist. For all the developed D-efficient designs, the covariates are mutually orthogonal to each other. The methods of construction of D-efficient covariate designs are developed with the help of a new matrix viz., Special Array (Das et. al., 2020). In this article, the series of developed D-efficient covariate designs are not available in the existing literature. International Journal of Statistical Sciences, Vol.24(1), March, 2024, pp 15-30

Understanding Chao (Biometrika, 1982) [Paper on ΠPS Sampling Schemes]

Chao's (1982) sampling scheme offers a systematic approach to select samples based on probability proportional to size (PPS) sampling without replacement but it might be difficult to grasp, particularly for entry-level researchers. In response, this study revisits Chao's method with the aim of providing a simplified and more intuitive understanding. Drawing inspiration from efforts by Dr. Tommy Wright and subsequent group discussions with BKS, we present a step-by-step breakdown of Chao's scheme with illustrative examples, emphasizing its elegance and practicality. This study showcases the value of making complex statistical methods accessible for broader engagement in research and practice. International Journal of Statistical Sciences, Vol.24(1), March, 2024, pp 133-154

Estimating Gain in Efficiency in Complicated Randomized Response Surveys versus Simpler Alternatives

Hartley and Ross’s (1954) ratio-type unbiased estimator for a finite population total based on a Simple Random Sample taken Without Replacement (SRSWOR) is examined for its performance versus the expansion estimator from the sample data at hand by Chaudhuri and Samaddar (2022). They also examined how Des Raj (1956) estimator based on PPSWOR performs against SRSWOR combined with expansion estimator using PPSWOR sample values. Here we study the expansion of them to Randomized Response survey data. International Journal of Statistical Sciences, Vol.24(1), March, 2024, pp 75-84

Indirect Questioning Technique Related to Sensitive Quantitative Variables with Options for Direct, Randomized and Item Count Responses

Randomized Response (RR) Technique (RRT) pioneered by Warner (1965) is a useful tool to elicit responses on sensitive characteristics, such as induced abortions, drug abuse, drunken driving, total amount of counterfeit notes of a particular denomination held by individuals in the population, etc. There exists a huge literature on Randomized Response (RR) devices for estimation of finite population mean of quantitative variables, sensitive in nature mostly based on Eichhorn and Hayre (1983). Device-I and Device-II vide Chaudhuri and Christofides (2013) allow estimation of population mean of sensitive quantitative variables using sample chosen by a general sampling design. On the other hand, Item Count Technique (ICT), described elaborately in Chaudhuri and Christofides (2013), is an alternative to RRT for respondents who do not choose to provide RRs. While some respondents may find a variable as sensitive, others may find it innocuous enough to provide a direct response (DR) about his/her true value. In such a case, Optional Randomized Response (ORR) Technique (ORRT) with options for DR and RR was introduced by Chaudhuri and Mukherjee (1985). Pal (2007) proposed an ORR device which offers choices for RR and ICT to the respondents for giving their answers. A new ORRT with options for DR, RR and ICT was provided by Shaw and Pal (2021) for eliciting indirect responses on sensitive characteristics. As this device relates to estimation of population proportion of sensitive characteristics, an attempt has been made to extend it for sensitive quantitative variables. Further, to take care of individuals’ varying choices for DR, RR and ICT and to protect the privacy of the respondents’ choices, this paper develops an ORR device allowing the respondents chosen by a general sampling design, to choose any one of the three options according to their choices.   International Journal of Statistical Sciences, Vol.24(1), March, 2024, pp 155-170

Ratio Type Estimator for Balanced Sampling Plan excluding Adjacent Units

The study variables are usually correlated with the auxiliary variables and therefore their correlation could easily be computed. In this paper, the correlation coefficient is used for the estimation procedure, and therefore, we proposed a Horvitz-Thompson ratio-type estimator using correlation coefficient for Balanced Sampling plan excluding Adjacent units (BSA plan). It has been illustrated theoretically and empirically that the proposed Horvitz-Thompson ratio-type estimator is more precise than the Horvitz-Thompson estimator based on BSA plan. The proposed estimator provides an opportunity to utilise the auxiliary information for the estimation of population mean for BSA plan and useful for many real-life experiments. International Journal of Statistical Sciences, Vol.24(1), March, 2024, pp 103-114

On the Sample Size Determination based on the Randomized Response Surveys

In general, the well known Chebyshev’s inequality is used to determine the sample size in order to conduct a survey using direct responses. The same technique intending to cover for sensitive variables are attempted recently by many statisticians. However it has been observed that in many cases the acceptable sample sizes are hard to be obtained, mainly because of appearance of some easily non-controllable part. Chaudhuri and Sen (2020), Chaudhuri and Patra (2023) and others have illustrated different situations and solutions are proposed therein. In this paper, following Chaudhuri, Bose and Dihidar (2011), we have made an attempt to deterimine the sample size corresponding to the estimators of sensitive population proportion using multiple randomized responses from distinct persons sampled. Along with the theoretical derivations, some numerical illustrations are presented. Based on the important extractions of our numerical illustration results, the recommendable sample size in practical real survey situations are observed. International Journal of Statistical Sciences, Vol. 24(1) March, 2024, pp 115-132

Some Questions Related to Rao-Blackwellization and Association Rule Mining

Prof. CR Rao has been awarded the prestigious 2023 International Prize in Statistics.  The citation reads: “In his remarkable 1945 paper published in the Bulletin of the Calcutta Mathematical Society, Calyampudi Radhakrishna (C.R.) Rao demonstrated three fundamental results that paved the way for the modern field of Statistics and provided statistical tools heavily used in science today……”. These three results are ‘Cramer-Rao Lower Bound’ (CRLB), ‘Rao- Blackwellization’ (RB) and the third one now flourished as ‘Information Geometry’. In this paper, we shall discuss two offshoots from his work over the eight decades. Several articles have appeared on his life and work (see for example, T. J. Rao (2019 and 2023a, 2023b) and Kumar (2023)).  The first offshoot is based on one of the three breakthrough results, namely, Rao–Blackwell Theorem, first proved by C.R. Rao in 1945, when he was just 25 years old and also by Blackwell later in 1947. The second one is on Association Rule Mining (ARM), which he developed when he was 96 years old. These two papers reveal the transition of statistical methodologies from Fisherian concepts to recent applications of AI and ML. In this paper we shall pose some questions which need further study. International Journal of Statistical Sciences, Vol.24(1), March, 2024, pp 85-89

On the Use of Inverse Exponentiation to Improve the Efficiency of Calibration Estimators in Stratified Double Sampling

This study introduces the concept of inverse exponentiation in formulating calibration weights in stratified double sampling and proposes a more improved calibration estimator based on Koyuncu and Kadilar (2014) calibration estimator. The variance of the proposed logarithmic calibration estimator has been derived under large sample approximation. Calibration asymptotic optimum estimator  and its approximate variance estimator are derived for the proposed logarithmic calibration estimator. Results of empirical study showed that the proposed logarithmic calibration estimator  performs better than the Koyuncu and Kadilar (2014) calibration estimator  with appreciable gains in efficiency. Also, simulation study for the comparison of the proposed logarithmic estimator with a Global estimator [Generalized Regression (GREG) estimator ] proved the robustness of the proposed logarithmic calibration estimator and by extension the efficacy of inverse exponentiation in calibration weightings.  Analysis and evaluation are presented. International Journal of Statistical Sciences, Vol.24(1), March, 2024, pp 91-102

Crafting Disaster-Driven Statistics: A Strategic Sampling Model

This article details the development and implementation of a strategic sampling methodology aimed at enhancing disaster-related statistics in Bangladesh. The study focuses on creating a specialized sampling frame by conducting a comprehensive census of enumeration areas (mouzas) affected by natural disasters. Employing a two-stage random sampling technique, the methodology incorporates stratification at district and disaster-type levels to capture diverse disaster occurrences. The Kish allocation method is utilized for sample allocation, addressing disparities in district sizes. Through meticulous trial and error simulations, the study ensures minimum sample sizes within each domain while employing inverse probability weights to estimate parameters. This strategic approach adopts robust estimations, enriching insights into disaster-related statistics. International Journal of Statistical Sciences, Vol.24(1), March, 2024, pp 49-64

Model Robust Optimal Designs for Kronecker Model for Mixture Experiments

In comparison to Scheffè’s canonical polynomial models (S-models), the Kronecker models (K-models) for mixture experiments are symmetric, compact in notation, and based on the Kronecker algebra of vectors and matrices. Further, there is a corresponding transition from S-models to K-models in the form of model re-parameterization. In the literature, it has been recommended to use second-degree K-models in practice compared to the widely used second-degree S-models especially when the moment matrix is of an ill-conditioning type. The motivation of the present article is to discriminate between K-models and S-models in terms of the model-robust D- and A-optimality criteria. These optimality criteria are discussed when there is uncertainty in selecting an appropriate model out of two rival models for a mixture experiment. International Journal of Statistical Sciences, Vol.24(1), March, 2024, pp 31-48

The Impact of High Government Debt on Economic Development in Somalia

This study focuses on the impact of high government debt on economic development in Somalia. The specific objectives of the study encompass: to examine the impact of high government debt on Somalia's economic development, to explore the strategies that can be used to mitigate the negative impact of high government debt on economic development in Somalia and to evaluate the role of international financial institutions in managing high government in Somalia. This study employed descriptive research design and quantitative research method to investigate the impact of heavily-indebted on rebuilding economic development in Somalia. The study employed purposive sampling technique to select the participants of the study. The sample size of the study was 80 participants. To collect data from the respondents which they entail: Government officials, Economic analysts, representatives from financial institutions, Business owners and entrepreneurs, representatives from Non-governmental organizations (NGOs) and Academics (researchers and scholars). The study adopted close-ended questionnaire instrument data collected from the respondents of the study was entered, coded, sorted, organized and analyzed using Statistical Package Software Science (SPSS) version 28. The key findings of the study on the impacts of high government debt on Somalia's economic development entail: limited access to credit, increased debt servicing costs, inflation and currency depreciation, reduced investor confidence, limited fiscal space, vulnerability to external shocks and social unrest. The strategies the can be used to mitigate the negative impact of high government debt on economic development in Somalia include: promotion of financial literacy, strengthening regulatory framework, encouragement of diversification of the economy, Improving infrastructure and access to financial services, implementation of debt management strategies, fostering a conducive business environment and seeking external assistance and debt relief. And the role of international financial institutions in managing high government debt in Somalia entail: providing financial assistance, negotiating debt relief, offering technical expertise and supporting capacity-building. The study recommended that the Federal Government of Somalia should improve fiscal management and should work with international financial institutions and creditor countries to negotiate debt relief and restructuring agreements to reduce the burden of debt payments and boost economic development.

Factors Influencing Obstetric Fistula among Women of Childbearing Age at Banadir Hospital, Somalia

This study focuses on the factors influencing obstetric fistula among the women of childbearing age at Banadir hospital, Somalia. The specific objectives of the study include: to identify the factors that contribute to obstetric fistula among women of childbearing age at Banadir Hospital in Somalia, to assess the impact of obstetric fistula on the physical, emotional, and social well-being of affected women at Banadir Hospital in Somalia and to explore potential interventions and strategies to prevent and manage obstetric fistula among women of childbearing age at Banadir Hospital in Somalia. The study also employed quantitative research approach research method to investigate the factors that contribute to obstetric fistula among women of childbearing age at Banadir Hospital in Somalia. The study utilised close-ended questionnaire instrument data collected from the respondents of the study was entered, coded, sorted, organized and analyzed using Statistical Package Software Science (SPSS) version 28. The findings of the study on factors that contribute to obstetric fistula among women of childbearing age at Banadir Hospital in Somalia which they include: lack of access to skilled obstetric care, poverty prevent women from seeking appropriate medical care during pregnancy and childbirth, lack of education, cultural and social factors, lack of access to clean water and sanitation and gender inequality. The impact of obstetric fistula on the physical, emotional, and social well-being of affected women at Banadir Hospital in Somalia include: chronic incontinence leading to foul-smelling leaks of urine and/or feces, which can cause skin irritation and infections, painful sores and ulcers in the genital area, malnutrition and dehydration due to difficulty in eating and drinking, chronic pelvic and abdominal pain, increased risk of reproductive health issues, including infertility and recurrent infections, feelings of shame, guilt, and isolation due to the stigma associated with obstetric fistula, depression, anxiety, and low self-esteem, loss of sense of self-worth and identity and trauma and social exclusion and discrimination from family, friends, and community members. The potential interventions and strategies to prevent and manage obstetric fistula among women of childbearing age at Banadir Hospital in Somalia entail: increasing access to skilled birth attendance by providing more trained healthcare providers, improving access to emergency obstetric care by ensuring that women have access to timely and appropriate medical care during childbirth, promoting family planning and contraception by empowering women to make informed choices about family planning and access to contraception, addressing cultural and social determinants by tackling underlying social norms and cultural practices that may contribute to obstetric fistula.

Prevalence of dysmenorrhoea and its associated factors among female medical students at Kampala International University Western Campus

The study aimed to determine the prevalence of dysmenorrhea and its associated factors among female medical students at Kampala international University–western campus. A descriptive cross sectional study design was conducted in order to determine the prevalence of dysmenorrhea and its associated factors among female medical students at Kampala International University Ishaka. A cross sectional study is chosen due to its ability to provide quantitative data. The study was conducted among female medical students that is; those offering certificate, diploma and bachelor nursing at Kampala International University western campus Ishaka. The study sampled 259 respondents to represent the whole population. The data collected was statistically analyzed and documented using Microsoft Excel. The excel file was imported into a software Statistical Package Social Sciences (SPSS) version 21. Among the respondents 6.9% had experience their first menstrual period at age of 12, 37.8% of the respondents experience at age of 12-14, 44.8% of the respondents experience at age 15-16 while 10.4% of the respondents experience at age of 16. It was concluded that prevalence of the dysmenorrhea is high in our study population. So, from the study it can be concluded that dysmenorrhea is a very common problem among girls, such high prevalence makes dysmenorrhea a significant public health problem among young students that demands some attention from policy makers. The recommended that enlightenment programmes should be organized periodically by the school health nurses on the various management strategies for menstrual disorders and how to use them effectively. Keywords: dysmenorrhea, menstrual period and disorders