Hasil untuk "Statistics"

Lawrence T. Lam, Lawrence T. Lam, Lawrence T. Lam et al.

BackgroundThis study aims to validate the Chinese version of the Short Warwick-Edinburgh Mental Well-being Scale (SWEMWBS) by employing both Classical Test Theory (CTT) and Item Response Theory (IRT) approaches.MethodsData were gathered through a population-based, cross-sectional health survey using an online self-reported questionnaire. The scale underwent Exploratory Factor Analysis (EFA) and Confirmatory Factor Analysis (CFA). Measurement invariance by gender was assessed using standard procedures. The Grade Response Model (GRM) of the IRT analysis was applied to the data, estimating the discrimination and difficulty parameters at different thresholds. The results were analyzed both graphically and through parameter values.ResultsFactor analyses confirmed that a single-factor model of the scale fit the data well, with an overall Eigenvalue of 4.55, explaining 65.0% of the total variance. Model fit statistics were slightly better for males than for females. Measurement invariance examinations also yielded satisfactory Goodness-of-Fit statistics (CFI = 0.940, TFI = 0.910, RMSEA < 0.001) with minimal changes in item loadings and indicator threshold patterns across groups. The IRT results demonstrated high discrimination parameters, ranging from 2.17 to 3.67, and nearly evenly distributed difficulty parameters, ranging from -2.23 to 1.77. Graphical examinations indicated good performance of the scale across the latent trait continuum.ConclusionsThe results indicated that, as a single-factor scale, the instrument exhibits good quality at both the scale and item levels. It has high discriminative power and an adequate response set for assessing a full range of the latent trait, namely mental well-being.

Imma Lory Aprea, Gianni Bosi, Gabriele Sbaiz et al.

In this paper, we tackle a bi-objective optimization problem in which we aim to maximize the portfolio diversification and, at the same time, minimize the portfolio volatility, where the ESG (Environmental, Social, and Governance) information is incorporated. More specifically, we extend the standard portfolio volatility framework based on the financial aspects to a new paradigm where the sustainable credits are taken into account. In the portfolio’s construction, we consider the classical constraints concerning budget and box requirements. To deal with these new asset allocation models, in this paper, we develop an improved Multi-Objective Particle Swarm Optimizer (MOPSO) embedded with ad hoc repair and projection operators to satisfy the constraints. Moreover, we implement a deep learning architecture to improve the quality of estimating the portfolio diversification objective. Finally, we conduct empirical tests on datasets from three different countries’ markets to illustrate the effectiveness of the proposed strategies, accounting for various levels of ESG volatility.

D.E. Ogolo, E.C. Ajare, O. Okwuoma et al.

Background and objectives: While various pathologies affecting the foramen magnum region can have severe consequences, little research has been conducted on the unique morphological patterns in the West African subregion. The study aimed to assess these patterns and their implications for surgeries, comparing them with global standards. Methods: A descriptive study was conducted on 315 patients over a two-year period, excluding those with specific abnormalities. Measurements obtained from cranial 1.5T MRI scans included anteroposterior and transverse diameters of the foramen magnum. From these, the foramen magnum area and index were calculated. The data was analyzed by inferential, comparative and descriptive statistics, and a p value < 0.05 was regarded as statistically significant. Results: On average, the transverse and anteroposterior diameters were 28.51 mm and 33.02 mm for males and 28.39 mm and 33.47 mm for females, with a slightly smaller foramen magnum area in males (7.42 cm²) compared to females (7.47 cm²). Despite these differences, the variations were not statistically significant. However, the foramen magnum indices indicated medium size configuration for females and large size configuration for males, aligning with global trends. Conclusion: The study concluded that West Africans exhibited lower foramen magnum area and indices compared to other regions, with minor differences between sexes. Females tended to have a medium size configuration, while males tended to have a larger size configuration. These findings provide valuable insights for clinicians, highlighting the importance of considering ethno-regional variations in surgical approaches and interventions related to the craniocervical junction.

Vladimir Tesar, Conor Judge, John Kelleher et al.

Objective ANCA-associated vasculitis (AAV) is a relapsing-remitting disease, resulting in incremental tissue injury. The gold-standard relapse definition (Birmingham Vasculitis Activity Score, BVAS&gt;0) is often missing or inaccurate in registry settings, leading to errors in ascertainment of this key outcome. We sought to create a computable phenotype (CP) to automate retrospective identification of relapse using real-world data in the research setting.Methods We studied 536 patients with AAV and &gt;6 months follow-up recruited to the Rare Kidney Disease registry (a national longitudinal, multicentre cohort study). We followed five steps: (1) independent encounter adjudication using primary medical records to assign the ground truth, (2) selection of data elements (DEs), (3) CP development using multilevel regression modelling, (4) internal validation and (5) development of additional models to handle missingness. Cut-points were determined by maximising the F1-score. We developed a web application for CP implementation, which outputs an individualised probability of relapse.Results Development and validation datasets comprised 1209 and 377 encounters, respectively. After classifying encounters with diagnostic histopathology as relapse, we identified five key DEs; DE1: change in ANCA level, DE2: suggestive blood/urine tests, DE3: suggestive imaging, DE4: immunosuppression status, DE5: immunosuppression change. F1-score, sensitivity and specificity were 0.85 (95% CI 0.77 to 0.92), 0.89 (95% CI 0.80 to 0.99) and 0.96 (95% CI 0.93 to 0.99), respectively. Where DE5 was missing, DE2 plus either DE1/DE3 were required to match the accuracy of BVAS.Conclusions This CP accurately quantifies the individualised probability of relapse in AAV retrospectively, using objective, readily accessible registry data. This framework could be leveraged for other outcomes and relapsing diseases.

Atefeh Ansarin, Dariush Shanehbandi, Habib Zarredar et al.

Introduction: Given the well-established association between metabolic syndrome (MetS) and obesity, this study elucidates the influences of sleep duration and weight on MetS risk and explores the potential role of miRNAs as underlying mechanisms. Methods: According to sleep logs and biochemistry tests, this study investigated the association between MetS and its components, sleep duration, and weight in four subgroups: A: normal sleepers with normal weight (N = 145), B: normal sleepers with obesity (N = 140), C: short sleepers with normal weight (N = 130), and D: short sleepers with obesity (N = 142). Chi-square, one-way ANOVA, and Tukey’s post hoc tests were used for statistical analysis. Furthermore, following total RNA isolation by TRIzol from blood samples, cDNA was synthesized using stem-loop technique. Quantitative real-time polymerase chain reaction (qRT-PCR) was then employed to evaluate the expression levels of miR-33a, miR-378a, miR-132-3p, and miR-181d. The data were analyzed using one-way ANOVA. Results: Our findings revealed the strongest association between MetS prevalence and individuals in group D (short sleepers with obesity; Cramer's V = 0.649, P < 0.001). This observation underscores the synergistic effect of short sleep and obesity on MetS risk. Furthermore, there was an independent association between short sleep duration and elevated triglyceride levels (P < 0.05). MicroRNA expression analysis revealed downregulation of miR-33a and miR-181d in B, C, and D groups compared to the normal group. Conversely, miR-132-3p expression was upregulated in the B, C, and D groups. Conclusion: Short sleep and obesity synergistically elevate MetS risk, potentially via miR-33a and miR-181d downregulation and miR-132-3p upregulation, impacting triglyceride metabolism.

Yanping Zheng, Hui Yang, Wenxia Wang

This paper is concerned with the existence and multiplicity of monotone positive solutions for a class of nonlinear fractional differential equation with a disturbance parameter in the integral boundary conditions on the infinite interval. By using Guo–Krasnosel’skii fixed-point theorem and the analytic technique, we divide the range of parameter for the existence of at least two, one and no positive solutions for the problem. In the end, an example is given to illustrate our main results.

Noor Hafizah Khairul Anuar, Mohd Amri Md Yunus, Muhammad Ariff Baharudin et al.

Environmental factors like temperature, solar irradiance, and rain may influence the health and productivity of stingless bees. This paper aims to investigate the best approaches applied in meliponiculture to predict beehive health and products based on environmental variables and bee activity data. The data on temperature, humidity, rain, beehive weight, and bee activity traffic utilized in this project were monitored in real-time and saved on the Google Spreadsheet platform. The dataset extracted from the 6th of January 2024 to the 5th of February 2024, at a 15-minute time interval comprising a total of 2577 data points was analyzed using various deep learning approaches for best RMSE performance. A single-layer LSTM model with 50 units produced the best RMSE performance of 0.039, representing that the beehive weight was accurately predicted. This predictive capability can help farmers determine the optimum harvesting time based on weight forecasts, ensuring maximum yield and quality. Additionally, by providing early warnings of unwanted conditions such as swarming or potential attacks, this method significantly enhances the ability of beekeepers to take proactive measures to protect their colonies, safeguarding both bee populations and the livelihoods of farmers.

Lyndon Ang, Robert Clark, Bronwyn Loong et al.

There is a growing trend among statistical agencies to explore non-probability data sources for producing more timely and detailed statistics, while reducing costs and respondent burden. Coverage and measurement error are two issues that may be present in such data. The imperfections may be corrected using available information relating to the population of interest, such as a census or a reference probability sample. In this paper, we compare a wide range of existing methods for producing population estimates using a non-probability dataset through a simulation study based on a realistic business population. The study was conducted to examine the performance of the methods under different missingness and data quality assumptions. The results confirm the ability of the methods examined to address selection bias. When no measurement error is present in the non-probability dataset, a screening dual-frame approach for the probability sample tends to yield lower sample size and mean squared error results. The presence of measurement error and/or nonignorable missingness increases mean squared errors for estimators that depend heavily on the non-probability data. In this case, the best approach tends to be to fall back to a model-assisted estimator based on the probability sample.

Lev Raskin , Larysa Sukhomlyn, Dmytro Sokolov et al.

Object of research is technical state of deteriorating systems whose operating conditions depend on a large number of interacting factors. The caused inhomogeneity of the sample of initial data on the technical state leads to impossibility of correct use of traditional methods of assessing the state of a system (meaning methods using mathematical tools of regression analysis). Subject of research is developing a method for constructing a regression polynomial based on the results of processing a set of controlled system parameters. Non-linearity of the polynomial describing the evolution of the technical state of real systems leads to an increase in the number of regression polynomial coefficients subject to estimation. The problem is further complicated by the growing number of factors affecting the technical state of the system. In these circumstances, the so-called <small sample effect> occurs.  Goal the research consists in developing a method for constructing an approximation polynomial that describes evolution of the system state in a situation where the volume of the initial data sample is insufficient for correct estimating coefficients of this polynomial. The results obtained. The paper proposes a method for solving the given problem, based on implementation of a two-stage procedure. At the first stage a functional description of the approximation polynomial coefficients is performed; and this radically reduces the number of regression polynomial parameters to be estimated. This polynomial is used for preliminary estimation of its coefficients with the aim of filtering out insignificant factors and their interactions. At the second stage, parameters of the truncated polynomial are estimated by means of using standard technologies of mathematical statistics. Two approaches to constructing a modified polynomial have been studied: the additive one and the multiplicative one. It has been shown that the additive approach is, on average, an order of magnitude more effective than the multiplicative one.

Maryam Fakhrzad, Ali Akbar Fazaeli, Yadollah Hamidi

Background: Catastrophic health expenditure (CHE) has been explained as a growth in spending for health care services that exceeds 40% of total household income. Therefore, devoting a large portion of household resources to health care services can greatly threaten to standards of living in the short and long term. The present study was an attempt to evaluate the financial contribution of Iranian households in health care services system in Hamadan Province in 2017.Methods: This cross-sectional study reflected on spending for health care services. For this purpose, the data were extracted from the household expenditure statistics published in the database of the Statistical Center of Iran. Accordingly, among the common econometric models associated with the subject matter, the logit model was employed, and the data were then analyzed using the Stata 14 software.Results: The study findings revealed that 8.9% of the total household costs had been allocated to health care services. The results also showed that 3.5% of the households faced catastrophic cost among all the studied households. Upon examining the factors, significant relationship was further observed between the probability of exposure to CHE and living in rural areas, income decile group, number of employees, and marital status in the households concerned.Conclusion: It was concluded that poor distribution of health care services, unequal distribution of income and wealth among jobs, as well as socioeconomic conditions could influence CHE. Therefore, there is a need to plan and develop policies for better access to health care services.

Adeel Aslam, Che Suraya Zin, Shazia Jamshed et al.

Self-medication with antibiotics (SMA) has become considerably common in developing countries, which is a critical factor for driving antibiotic resistance. Individuals involved in SMA generally do not have adequate knowledge regarding the appropriate use, indications and dosage of these drugs. The objective of the present study was to investigate population SMA practices, knowledge and sociodemographic factors associated with SMA in Islamabad, Pakistan. The study adopted a cross-sectional methodology and data collection was performed through an anonymous, structured and pilot-tested questionnaire, which was interview-administered. Inferential statistics and multivariate logistic regression were performed. Out of 480 participants, 55.6% (<i>n</i> = 267) were male with a mean age of 37.1 ± 10.1 years; the total prevalence of SMA was 32.5%. Ciprofloxacin (42.9%) was the most commonly used antibiotic to treat coughs or colds, a runny nose, flu or sore throat, diarrhea or fevers, which were relevant reasons for SMA. Findings from multivariate logistic regression showed that predictors of SMA were: male gender (95% CI: 0.383–1.005), age (95% CI: 0.317–0.953) and highest level of education (95% CI: 0.961–0.649). Despite reasonable access to healthcare facilities, people are still obtaining antibiotics without prescription, bypassing diagnostic and consultative healthcare services. Thus, the government must implement strict healthcare policies to restrict the sale of antibiotics without prescriptions, while at the same time, targeted public awareness campaigns about the proper use of antibiotics are also required.

Federico Bergamin, Pierre-Alexandre Mattei, Jakob D. Havtorn et al.

We present simple methods for out-of-distribution detection using a trained generative model. These techniques, based on classical statistical tests, are model-agnostic in the sense that they can be applied to any differentiable generative model. The idea is to combine a classical parametric test (Rao's score test) with the recently introduced typicality test. These two test statistics are both theoretically well-founded and exploit different sources of information based on the likelihood for the typicality test and its gradient for the score test. We show that combining them using Fisher's method overall leads to a more accurate out-of-distribution test. We also discuss the benefits of casting out-of-distribution detection as a statistical testing problem, noting in particular that false positive rate control can be valuable for practical out-of-distribution detection. Despite their simplicity and generality, these methods can be competitive with model-specific out-of-distribution detection algorithms without any assumptions on the out-distribution.

Aleksandra Slavkovic, Jeremy Seeman

To quantify trade-offs between increasing demand for open data sharing and concerns about sensitive information disclosure, statistical data privacy (SDP) methodology analyzes data release mechanisms which sanitize outputs based on confidential data. Two dominant frameworks exist: statistical disclosure control (SDC), and more recent, differential privacy (DP). Despite framing differences, both SDC and DP share the same statistical problems at its core. For inference problems, we may either design optimal release mechanisms and associated estimators that satisfy bounds on disclosure risk, or we may adjust existing sanitized output to create new optimal estimators. Both problems rely on uncertainty quantification in evaluating risk and utility. In this review, we discuss the statistical foundations common to both SDC and DP, highlight major developments in SDP, and present exciting open research problems in private inference.

Yong-Min Li, M. Ijaz Khan, Sohail A. Khan et al.

Abstract Entropy optimization in convective viscous fluids flow due to a rotating cone is explored. Heat expression with heat source/sink and dissipation is considered. Irreversibility with binary chemical reaction is also deliberated. Nonlinear system is reduced to ODEs by suitable variables. Newton built in shooting procedure is adopted for numerical solution. Salient features velocity filed, Bejan number, entropy rate, concentration and temperature are deliberated. Numerical outcomes for velocity gradient and mass and heat transfer rates are displayed through tables. Assessments between the current and previous published outcomes are in an excellent agreement. It is noted that velocity and temperature show contrasting behavior for larger variable viscosity parameter. Entropy rate and Bejan number have reverse effect against viscosity variable. For rising values of thermal conductivity variable both Bejan number and entropy optimization have similar effect.

Judith J. Lok, Department of Mathematics, Statistics et al.

Coarse structural nested mean models are used to estimate treatment effects from longitudinal observational data. Coarse structural nested mean models lead to a large class of estimators. It turns out that estimates and standard errors may differ considerably within this class. We prove that, under additional assumptions, there exists an explicit solution for the optimal estimator within the class of coarse structural nested mean models. Moreover, we show that even if the additional assumptions do not hold, this optimal estimator is doubly-robust: it is consistent and asymptotically normal not only if the model for treatment initiation is correct, but also if a certain outcome-regression model is correct. We compare the optimal estimator to some naive choices within the class of coarse structural nested mean models in a simulation study. Furthermore, we apply the optimal and naive estimators to study how the CD4 count increase due to one year of antiretroviral treatment (ART) depends on the time between HIV infection and ART initiation in recently infected HIV infected patients. Both in the simulation study and in the application, the use of optimal estimators leads to substantial increases in precision.

KS Kylie Lee, Michelle S. Fitts, James H. Conigrave et al.

Abstract Background Population estimates of alcohol consumption vary widely among samples of Aboriginal and Torres Strait Islander (Indigenous) Australians. Some of this difference may relate to non-representative sampling. In some communities, household surveys are not appropriate and phone surveys not feasible. Here we describe activities undertaken to implement a representative sampling strategy in an urban Aboriginal setting. We also assess our likely success. Methods We used a quota-based convenience sample, stratified by age, gender and socioeconomic status to recruit Indigenous Australian adults (aged 16+) in an urban location in South Australia. Between July and October 2019, trained research staff (n = 7/10, Aboriginal) recruited community members to complete a tablet computer-based survey on drinking. Recruitment occurred from local services, community events and public spaces. The sampling frame and recruitment approach were documented, including contacts between research staff and services, and then analysed. To assess representativeness of the sample, demographic features were compared to the 2016 Australian Bureau of Statistics Census of Population and Housing. Results Thirty-two services assisted with data collection. Many contacts (1217) were made by the research team to recruit organisations to the study (emails: n = 610; phone calls: n = 539; texts n = 33; meetings: n = 34, and one Facebook message). Surveys were completed by 706 individuals – equating to more than one third of the local population (37.9%). Of these, half were women (52.5%), and the average age was 37.8 years. Sample characteristics were comparable with the 2016 Census in relation to gender, age, weekly individual income, Indigenous language spoken at home and educational attainment. Conclusion Elements key to recruitment included: 1) stratified sampling with multi-site, service-based recruitment, as well as data collection events in public spaces; 2) local services’ involvement in developing and refining the sampling strategy; and 3) expertise and local relationships of local Aboriginal research assistants, including health professionals from the local Aboriginal health and drug and alcohol services. This strategy was able to reach a range of individuals, including those usually excluded from alcohol surveys (i.e. with no fixed address). Carefully pre-planned stratified convenience sampling organised in collaboration with local Aboriginal health staff was central to the approach taken.

Wipapan Adulcharoen, Kallaya Suntornvongsakul, Yang-Soo Lee

Understanding the function of the ecological restoration of mangrove forests leads to appropriate sustainable utilization (SU) of ecosystem services (ES) during development stages of mangrove ecosystem for sustaining the local livelihood and maintaining the mangrove ecological production. The study aims to identify the SU which was changed relying a development of ES at Klong Khone (KK) Sub-district, Samut Songkhram Province, Thailand. The SU was collected by in-depth interview with 20 key respondents, questionnaires survey with 140 fishermen and statistical scientific data on developed mangrove forest areas. Descriptive statistics and event analysis were employed to analyze the data. The study found that bottom-up management tools based on a local people’s participation were applied to determine a way of harvest of ES. An application of these local tools including a common property right, land use zoning, application of local knowledge, human resources, and financial and technological transfer resulted in different utilizing activities of ES during the development of mangrove forest restoration stages. The results showed that the ES produced during mangrove stand initiation stage were mainly harvested for food (90%) and during the young forest regrowth stage (87%) (N = 140). They were also widely used for operating aquaculture during mangrove stand initiation stage (39%), but they were harvested with more concerns about environmental impacts during the young forest regrowth stage (47%) (N = 140). The cultural services during young forest regrowth stage were increasingly utilized for diversified incomes from ecotourism (46%) and education learning program (50%) (N = 140). The ES from developed mangrove forest were harvested effectively based on an application of SU tools which were locally developed by local people’s participation. The SU tools can be proposed and applied in other communities where have similar ecological, social and cultural conditions as KK sub-district to support the SU of ES.

Pedro V. Munuera-Martínez, Priscila Távara-Vidalón, Manuel A. Monge-Vera et al.

Several methods have been described to quantify the first ray mobility. They all have certain disadvantages (great size, sophistication, or lack of validation). The objective of this work was to study the validity and reliability of a new instrument for the measurement of first ray mobility. Anterior-posterior radiographs were obtained from 25 normal feet and 24 hallux valgus feet, with the first ray in a neutral position, maximally dorsiflexed and maximally plantarflexed. The first ray mobility was radiographicaly measured in both groups, and was also manually examined with the new device. A cluster analysis determined whether normal and hallux valgus feet were correctly classified, and a graphic analysis of Bland-Altman was performed to compare the radiographic and manual measurement techniques. Based on the radiographs, the first ray mobility only showed significant differences in dorsiflexion between both groups (<i>P</i> = 0.015). First ray dorsiflexion, plantarflexion and total range of motion measured with the new device were different between both groups (<i>P</i> = 0.040, <i>P</i> = 0.011 and <i>P</i> = 0.006, respectively). The silhouette measure of the cohesion and separation coefficients from the cluster analysis was greater than 0.50 for the dorsiflexion, plantarflexion and total range of motion obtained from the radiographs and from the new device. The Bland-Altman graph suggested that 96% of the data presented agreement between both measurement methods. These results suggested that the new instrument was valid and reliable.

Veronika Hannus

The presented data informs about a comprehensive online survey on the perception and acceptance of farm sustainability standards amongst German farmers. We conducted the online interviews, with a total of 598 adequately answered questionnaires in summer 2017. The resulting sample is representative of German farmers, as the distribution of participants corresponds very well to the percentage distribution of farms in Germany. The survey contained a discrete choice experiment (DCE), a structured survey of 30 sub-aspects of rewards to be expected from the application of a sustainability standard and a risk elicitation lottery choice-task. Besides, the personal characteristics of the farmers (e.g. gender, education, communication behaviour, age) and farm characteristics (e.g. farm type, size, labour, profit) were recorded. Since the complete raw dataset cannot be published due to the privacy rights of human subjects and the stated data use agreement (DUA) with the participants, the present article demonstrates the data collection process, describes the parameter of the DCE and, present summary statistics of the sample. In addition, we illustrate the variables coding and data structure using a model data set with 10 generated entries. Further, a reduced and edited exercise dataset, which is structured analogous to the real dataset, is used to demonstrate the analysis of the DCE data step-by-step. The results and the interpretation of the actual DCE data analysis are published in the article 'Acceptance of sustainability standards among farmers' - empirical evidence from Germany' [1]. The survey data can provide further insights on farmers' expected rewards from participating in a sustainability standard, on the role of risk perception and tolerance of German farmers, and the role of communication behaviour in the innovation adoption context.

Asta Cekaite, Mats Andrén

The present study investigates how laughter features in the everyday lives of 3–5-year old children in Swedish preschools. It examines and discusses typical laughter patterns and their functions with a particular focus on children's and intergenerational (child-adult/educator) laughter in early education context. The research questions concern: who laughs with whom; how do adults respond to children's laughter, and what characterizes the social situations in which laughter is used and reciprocated. Theoretically, the study answers the call for sociocultural approaches that contextualize children's everyday social interaction, e.g., in different institutions or homes, to study the diverse conditions society forms for learning, sociality, and socialization and development of shared norms. Methodologically, the study makes use of mixed methods: it uses descriptive statistics that identify prevalent patterns in laughter practices and, on the basis of these results, examines social-interactional situations of children's laughter in detail. It was found that children's laughter tended to be directed to children and adults' laughter tended to be directed to adults. Eighty seven percent of children's laughter was directed to other children, and adults directed their laughter to other adults 2.7 times as often as to children. The qualitative interaction analysis shows that children and adults exhibited different patterns of laughter. Children primarily sought and received affiliation through laughter in the peer group, and the adults were often focused on the institutional and educational goals of the preschool. Overall, the study shows that intergenerational reciprocal laughter was a rare occurrence and suggests that laughter between generations is interesting in that it can be seen as indicative of how children and adults handle alterity in their everyday life. By deploying multiple methods, the present study points to the importance of viewing emotion and norm sharedness in social interaction not just as a matter of communicating an emotion from one person to another, but as an intricate process of inviting the others into or negotiating the common emotional and experiential ground.