Range Of Statistical Tests Research Articles

Trend analysis of precipitation, temperature and snow water equivalent in Lombardy region, northern Italy

The analysis of precipitation, temperature, and snow water equivalent (SWE) trends offers a scientific approach for understanding the impacts of climate change. This paper presents a comprehensive analysis of climate change indicators in Lombardy, Italy, covering the yearly and monthly trends of precipitation and temperature from 1990 to 2020. Additionally, the yearly and monthly SWE variations. For this purpose, a range of statistical tests have been used including Mann–Kendall, Pettitt’s change point detection and Sen’s slope estimator. Precipitation trend shows a slight annual increase of around 5.42 mm per year. This trend is not statistically significant with a Mann–Kendall p value of 0.1448 and no changing point has been detected. Moreover, seasonal precipitation patterns show minor variations, with Kendall’s Tau values ranging from − 0.0431 to 0.1761. However, none of these trends are statistically significant, as reflected in Mann–Kendall p values ranging from 0.1679 to 0.7339. Conversely, Lombardy is experiencing a significant annual temperature increase of 0.0436 °C. Notably, in Autumn, temperatures rise at a rate of 0.0565° per year. Summer also shows a significant warming trend, with temperatures increasing by 0.0421° per year. In Winter and Spring, there are milder, non-significant temperature trends, with Kendall’s Tau values around 0.17. SWE trend shows minor annual variations (5–10%) and monthly shifts. Winter shows a slight decrease (2–3%), implying delayed snow accumulation, while Spring indicates minor change (1–2%) suggesting earlier snowmelt. This study emphasizes temperature's strong impact on SWE and stresses the importance of climate monitoring and collaboration for understanding changing climate patterns.

Understanding the Consumer Dynamics of AI in North Macedonian E-Business

Abstract Research Purpose This study investigates the dynamics of Artificial Intelligence (AI) in e-business, particularly from the perspective of consumers in North Macedonia. The research aims to identify and evaluate the benefits and challenges of AI integration in e-business, explore the ethical concerns related to AI decision-making, and understand the impact of AI on consumer behaviour and preferences. Design/Methodology/Approach The research adopts a mixed-methods approach, integrating qualitative and quantitative analyses. Primary data was collected via a structured questionnaire distributed among various demographic groups to gauge the level of awareness and experiences with AI in e-business. A range of statistical tests, including ANOVA and correlation tests, were employed to assess the significance of the data collected and to test a set of hypotheses concerning consumer perceptions and experiences of AI. Findings The results reveal that demographic factors such as age, status, education, and occupation do not significantly impact the level of understanding, awareness, or experiences with AI among Macedonian consumers. Participants exhibited a level of high awareness of the importance of AI in e-business and rated their shopping experiences with AI more positively than traditional methods. Trust and reliability in AI did not significantly differ across demographic lines. The findings of this study have significant policy implications, especially in guiding the ethical and responsible integration of AI in e-business. They suggest a need for policies emphasising consumer data protection and privacy, given the heightened awareness and concern among consumers regarding using their personal information. Furthermore, the results advocate for the development of regulatory frameworks that ensure transparency and fairness in AI algorithms, addressing potential biases that could negatively impact consumer trust. Originality/Value/Practical Implications This research contributes novel insights into the Macedonian consumer market’s perception of AI in e-business, a topic scarcely covered in existing literature. The findings underscore the necessity for businesses to adopt AI responsibly and ethically, highlighting the importance of prioritising fairness, privacy, and transparency to leverage AI’s full potential in e-business. This study stands out in its exploration of AI in e-business from the consumer perspective in North Macedonia, a context not extensively covered in existing literature. The originality of our research lies in its focus on a comprehensive range of consumer-centric factors, including awareness, experiences, ethical concerns, and behaviour related to AI in e-business.

DETERMINANTS OF GDP PER CAPITA IN BANGLADESH: AN EMPIRICAL STUDY

When making cross-country comparisons regarding the well-being and economic conditions of a population, GDP per capita is the most commonly used indicator. Hence, various economic indicators can affect GDP per capita. This study investigates the impact of inflation, exchange rate, and total reserves (including gold and USD) on GDP per capita in Bangladesh. The study employs a quantitative approach and follows a longitudinal research design. Time series data from 2012 to 2021 is collected using a stratified random sampling technique from the World Development Indicators provided by the World Bank. A range of statistical tests, such as Normality Test, Multivariate Outlier Analysis (Mahalanobis Distance), Multicollinearity Assessment (Tolerance and VIF), Goodness-of-Fit (GoF) Test, ANOVA Test, and Multiple Regression Analysis, were performed using SPSS v.22. The results reveal that exchange rate has a significant influence on GDP per capita, making it crucial factor for economic development, resilience, and export competitiveness. Total reserves were found to have minimal relation with GDP per capita. In contrast, inflation rate, although adversely impacting GDP per capita, remains important for maintaining overall economic stability. Thus, the findings of this study suggest that effective currency management is paramount for economic development.

Assessment of hydrological barriers effect in river benthic fauna coupled with eDNA metabarcoding monitoring

Anthropogenic activities alter the rivers’ hydromorphological characteristics, affecting the ecosystems. River continuum interruption is identified as a principal cause of longitudinal quality variation. Macroinvertebrates, the most common biological quality indicator, are usually coupled with hydromorphological alteration assessment protocols. Environmental DNA (eDNA) metabarcoding is a recent advance in biomonitoring, complementing classical assessment, responding to time and cost-efficiency limitations. This study assesses the hydromorphological effects of two barriers (sluice and rock ramp) in a large Mediterranean modified river on the structure of macroinvertebrate assemblages using the classical method, coupled with eDNA metabarcoding while it further correlates them with the alteration of the riparian zone. Samplings were conducted at three stations for each barrier, one upstream and two downstream, during high and low flow periods. A range of statistical tests were performed for the assemblages’ comparison, the diversity indices and the investigation of spatial and temporal patterns. The findings include differences among communities’ composition for the two approaches with a moderate overlap between eDNA and classical taxonomy. The ramp had lower influence on biota in comparison to the sluice. Regarding the spatial pattern, no significant differences were revealed for both methods, but it could be attributed to the barriers’ operation extent. As for a temporal pattern, there was a difference between the two methods and, while no separation was noted among the sites as a sum, site-specific differences were found. If some problems concerning the taxonomic assignment of ASVs, the sampling methodology and the primers selection are surpassed, eDNA proves a valuable tool.

Evaluation of High-Resolution Satellite-Derived Solar Radiation Data for PV Performance Simulation in East Africa

Access to reliable, clean, modern cooking enhances life chances. One option is photovoltaic cooking systems. Accurate solar data are needed to ascertain to what extent these can satisfy the needs of local people. In this paper, we investigate how to choose the most accurate satellite-derived solar irradiance database for use in Africa. This is necessary because there is a general shortage of ground measurements for Africa. The solar data are needed to model the output of solar cooking systems, such as a solar panel, battery and electric pressure cooker. Four easily accessible global horizontal irradiation (GHI) satellite databases are validated against ground measurements using a range of statistical tests. The results demonstrate the impact of the mathematical measure used and the phenomenon of balancing errors. Fitting of the satellite model to the appropriate climate zone and/or nearby measurements improves accuracy, as does higher spatial and temporal resolution of input parameters. That said, all the four databases reviewed were found to be suitable for simulating PV yield in East Africa.

The Link between Documentation Status, Occupation Status, and Healthcare Access for African migrants

The link between migrants’ legal and employment status, access to health and health outcomes is widely explored in the academic literature on migration and health. However, there are few, if any, studies examining this link within African states. In this article we present survey data collected from refugees and people in refugee-like situations in Kenya, regular (labor) migrants in Nigeria, and irregular migrants in South Africa to examine the link between registration status, employment or occupation status, gender, and (perceptions of) access to healthcare. A range of statistical tests and models were applied to examine the effects of these different characteristics. A consistent finding throughout the three sample countries is that access for people without any documentation is lower than different other groups, not only by means but also within the linear models. This strongly suggests that extending regularization pathways in African states, even if on a temporary basis, would be an effective policy lever to improve migrants’ access to healthcare, and by extension migrants’ health. However, the effects of employment status and gender on access to healthcare were more ambiguous, and further research in African contexts is required to clarify their impact.

The Role of Organizational Culture in Intellectual Capital: A Case Study of Salahuddin University-Erbil

This paper's purpose is to examine the role of organizational culture on intellectual capital as a case study conducted at Salahaddin University colleges in Erbil. That represented in all 14 colleges in Erbil, then distributing (88) questionnaire forms on the respondents, (82) valid form were obtained for analysis. So, the method adopted by the research is to identify the research problem by asking several questions centered on the nature of the relationship and effect between the research variables. Although a conceptual scheme designed to establish and test the research hypotheses through a range of statistical tests. However, a descriptive analytical method was used to reach the research results. Hence, Spearman correlation and multiple regression analysis respectively applied in order to determine the degree of the relationship and prediction of intellectual capital. As a result, this paper reached some conclusions, most notably presence the importance of the organizational culture and intellectual capital components. Moreover, the results showed that the organizational culture and it is components have an essential relationship in forming intellectual capital. Besides, the study found the organizational culture effect on intellectual capital.

Psychometric evaluation of the PROMIS\xae Depression Item Bank: an illustration of classical test theory methods

BackgroundPsychometric theory offers a range of tests that can be used as supportive evidence of both validity and reliability of instruments aimed at measuring patient-reported outcomes (PRO). The aim of this paper is to illustrate psychometric tests within the Classical Test Theory (CTT) framework, comprising indices that are frequently applied to assess item- and scale-level psychometric properties of PRO instruments.MethodsUsing data on the PROMIS Depression Item Bank, typical CTT indices for the assessment of psychometric properties are illustrated, including content validity, item-level data exploration, reliability, and construct validity, particularly confirmatory factor analysis, to test the unidimensionality assumption underlying the item bank. Analyses are carried out on an original item set of 51 depression items, the final (official) PROMIS Depression Item Bank consisting of 28 items, and an 8-item short form.ResultsThe analyses reported provide an informative illustration on how item- and scale-level reliability and validity statistics can be used to assess the psychometric quality of a PRO instrument. The results illustrate how the reported statistics can be used for item selection from an item pool (here: 51 items). Both the (final) 28-item bank and the 8-item short form show good psychometric properties supporting the high quality of individual items and the unidimensionality assumption of the item bank.ConclusionsIt is our hope that our illustration of CTT methods, in conjunction with two companion papers illustrating modern test theory methods, will help researchers to confidently apply a range of statistical tests to evaluate item- and scale-level psychometric performance of PRO instruments.

Want Smart Beta? Follow the Smart Money: Market and Factor Timing Using Relative Sentiment

We present a real-time, cross-asset, positions-based relative sentiment indicator to predict the U.S. equity market. Derived from the Commitments of Traders report, the indicator measures — in a novel way — the aggregate positioning in equities of institutional investors relative to individual investors. Applying a wide range of statistical tests and controlling for data snooping, we find this indicator to be highly significant, exceptionally robust, and substantially more powerful than both value and momentum in predicting equity returns. Beyond the broad market, the indicator also facilitates the timing of several “smart beta” equity factors — many of which were thought difficult or impossible to time. We propose a tactical asset allocation strategy based on the indicator and compare it to several value- and/or momentum-based alternatives — finding the proposed strategy produces higher returns (both absolute and risk-adjusted), while having considerably less time-averaged exposure to equities.

The effects of environmental and visitor variables on the behavior of free-ranging ring-tailed lemurs (Lemur catta) in captivity.

The effect of the zoo environment on captive animals is an increasingly studied area of zoo research, with visitor effects and exhibit design recognized as two of the factors that can contribute to animal welfare in captivity. It is known that in some situations, visitors may be stressful to zoo-housed primates, and this may be compounded by environmental factors such as the weather, the time of day, and zoo husbandry routines. Exhibit design and proximity of the public are also known to influence behavioral response of primates to visitors; however, there is minimal research on free-ranging zoo animals, even though they are potentially subjected to intense interactions with visitors. The current study explores the effect of the zoo environment, several visitor variables and specific animal-visitor interactions on the behavior of free-ranging ring-tailed lemurs (Lemur catta) at Fota Wildlife Park, Ireland. Data were obtained through scan samples collected over 18 months (n = 12,263) and analyzed using a range of statistical tests, including general estimating equations (GEE). Results demonstrate that the free-ranging lemurs' behavior at Fota Wildlife Park is affected by season, weather and time of day. Similarities in feeding behavior exist between the free-ranging group and lemurs in the wild when resources are plentiful. Visitor variables had a limited effect on lemur behavior and behavioral diversity level. Lemurs rarely reacted to visitors when specific interactions were considered. Generally, the results indicate that the ring-tailed lemurs in this study have adapted well to the zoo environment and habituated to visitors.

Implications of Modelled Climate and Land Cover Changes on Runoff in the Middle Route of the South to North Water Transfer Project in China

Sustainable management of water for human uses and maintaining river health requires reliable information about the future availability of water resources. We quantified the separate and combined impacts of climate and land cover changes on runoff for the historical record and for modelled future scenarios in the upper Han River and Luan River, supply and demand zones respectively of the middle route of the South to North Water Transfer Project in China, the world’s largest inter-basin water transfer project. We used a precipitation-runoff model, averaged multiple climate model predictions combined with three emissions scenarios, a combined CA-Markov model to predict land cover change, and a range of statistical tests. Comparing baseline with 2050: climate change would cause an average reduction in runoff of up to 15 % in the upper Han River and up to 9 % in the Luan River catchment; a scenario involving increased forest cover would reduce runoff by up to 0.19 % in the upper Han River and up to 35 % in the Luan River; a scenario involving increased grass cover would increase runoff by up to 0.42 % in the upper Han River and up to 20 % in the Luan River. In the lower Luan River, the mean annual flow after 1998 fell to only 17 % of that of the baseline period, posing a serious threat to river health. This was explained largely by extraction of surface water and groundwater, rather than climate and land use change.

The equivalence of single-item scales of psychic distance: A test in Brazil

Despite the broad acceptance of the concept of psychic distance, problems related to measuring the construct have persisted in empirical studies. Although researchers have developed and used a variety of instruments, no study has, thus far, concerned itself with making a comparative evaluation for the purpose of assessing their equivalence. The present study sought to evaluate several single-item scales to measure psychic distance as a summary construct. Four data collection instruments in the literature were identified, and applied to a final sample of 365 university students. Approximately one fourth of the sample answered each questionnaire. A range of statistical tests were carried out in order to identify the features of the respective instruments as well as to assess their equivalence and validity. The results enabled to compare features and showed that only two of the instruments produced equivalent results. All of the scales correlated strongly; however, the performance of the scales in the tests did vary. The Stottinger and Schlegelmilch (1998) scale has the capacity to be used with a greater range of statistical tests and presented superior results in practically all of the tests carried out. It is the scale recommended to researchers wishing to utilize single-item measures of psychic distance. Key words: psychic distance, measurement scales, summary construct, single-item scales.

C-Reactive Protein and Prognosis in Diabetes: Getting to the Heart of the Matter

C-reactive protein (CRP) is a liver-derived protein whose concentration increases manyfold during inflammation or infection, making it a useful diagnostic and treatment measure in diseases such as rheumatoid arthritis. However, in the last decade, CRP has garnered interest as a biomarker of vascular risk that has stimulated more studies than perhaps any other “novel” biomarker. In these studies, the much lower CRP values seen in healthy individuals free from overt infection or inflammation, detected by a new generation of sensitive assays, have been associated in study after study with the risk of a first cardiovascular event (rev. in (1). Yet, despite the consistency of this association, whether CRP is causally involved in atherogenesis or whether it helps in prediction of cardiovascular disease (CVD) events remains intensely controversial (2,3). In light of this controversy, studies examining the association of CRP with vascular outcome and mortality in patient populations, such as those with diabetes, where prospective data remain relatively sparse are to be welcomed. In the current issue of Diabetes , Bruno et al. (4) report that although CRP was related to risk of all-cause and CVD mortality in their 5-year follow-up of the Casale Monferrato Study, the improvement in individual risk prediction beyond established risk markers, evaluated by a range of statistical tests, was marginal at best. The results from this helpful study, therefore, currently caution against routine measurement of CRP for risk prediction in diabetes patients. Why should CRP not better predict risk in individuals, given its consistent association with CVD and mortality? Several issues contribute. The association of CRP with incident events is linear when both CRP values and risk are plotted on …

Continental Shift? An Analysis of Convergence Trends in European Real Estate Equities

This article is the winner of the International Real Estate Investment/Portfolio Management category (sponsored by LaSalle Investment Management) presented at the 2002 American Real Estate Society Annual Meeting.This study investigates the effects of European monetary integration on the behavior of stock returns in European real estate companies from the perspective of a dollar-denominated investor. A range of statistical tests is applied to assess changes in segmentation, co-movement and causality. The results suggest that, relative to the wider equity markets, the dispersion of performance is higher, correlations are lower and a common contemporaneous factor has much lower explanatory power whilst lead-lag relationships are stronger. Less and slower integration is attributed to the relatively small size of the real estate securities market and the local nature of many real estate companies' portfolios.

PERCEPTION-BASED ANALYSIS OF ENGINEERING EXPERIMENTS IN THE SEMICONDUCTOR INDUSTRY

Comparing frequency distributions of experimental data is a routine engineering task in the semiconductor industry. The existing statistical approaches to the problem suffer from several limitations, which can be partially overcome via the time-consuming visual examination of frequency histograms by an experienced process engineer. This paper presents a novel, fuzzy-based method for automating the cognitive process of comparing frequency histograms. We use the evolving approach of type-2 fuzzy logic to utilize the domain knowledge of human experts. The proposed method is evaluated on the actual results of an engineering experiment, where it is shown to represent the experts' perception of the visualized data more accurately than a wide range of statistical tests. We also outline the potential directions for integrating the perception-based approach with other methods of data visualization and data mining.

Long‐term ant community responses to selective harvesting of timber from Spotted Gum (Corymbia variegata)‐dominated forests in south‐east Queensland

Summary The conservation of biological diversity is a fundamental consideration in the management of production forests in eastern Australia. Invertebrate communities make up the bulk of diversity in these forests, yet few studies have been conducted to determine what impact, if any, timber harvesting may have on their structure, dynamics or diversity. We report here on a space‐for‐time study conducted in an open eucalypt production forest in south‐east Queensland that investigated the long‐term effects of selective timber harvesting on the ground‐active ant community. Over a notional 30–40 year logging cycle, there were significant changes in the composition of ant functional groups, no significant changes to ant abundance and a weak trend to reduced ant species richness as time since harvesting increased. However, when ant community composition was compared with logging history and other environmental variables using a range of statistical tests, only small changes in ant community composition were attributable to timber harvesting. This suggested that the ant community was at least partially controlled by factors other than management history or the environmental variables measured in this study. The diversity, abundance and organization of ant communities is therefore unlikely to be detrimentally affected by selective harvesting of timber, as currently practiced in state‐owned forests in south‐east Queensland.

Is Strategic Planning Worth the Effort? A Study of Firm Performance Versus Planning Comprehensiveness in Australia

AbstractThe planning-performance literature suggests that there is a weak positive correlation between strategic planning and financial performance. This study has been undertaken to determine whether this weak positive correlation is true for Australian firms.Strategic planning for the purposes of this study is arranged in three levels of planning complexity. A sample of 77 listed firms was surveyed to determine their level of planning complexity, and this was correlated with the firm's financial performance over a three year period.A range of statistical tests did not reveal any significant correlation between strategic planning at any of the three levels and the financial performance of the firm. This negative finding is generally in line with other recent studies conducted in Australia, the United States and the United Kingdom.However, positive correlations were found with several subjective performance measures, suggesting that respondents generally believe that strategic planning is helping their company.

Is Strategic Planning Worth the Effort? A Study of Firm Performance Versus Planning Comprehensiveness in Australia

AbstractThe planning-performance literature suggests that there is a weak positive correlation between strategic planning and financial performance. This study has been undertaken to determine whether this weak positive correlation is true for Australian firms.Strategic planning for the purposes of this study is arranged in three levels of planning complexity. A sample of 77 listed firms was surveyed to determine their level of planning complexity, and this was correlated with the firm's financial performance over a three year period.A range of statistical tests did not reveal any significant correlation between strategic planning at any of the three levels and the financial performance of the firm. This negative finding is generally in line with other recent studies conducted in Australia, the United States and the United Kingdom.However, positive correlations were found with several subjective performance measures, suggesting that respondents generally believe that strategic planning is helping their company.

ACORN—A new method for generating sequences of uniformly distributed Pseudo-random Numbers

A new family of pseudo-random number generators, the ACORN ( additive congruential random number) generators, is proposed. The resulting numbers are distributed uniformly in the interval [0, 1). The ACORN generators are defined recursively, and the ( k + 1)th order generator is easily derived from the kth order generator. Some theorems concerning the period length are presented and compared with existing results for linear congruential generators. A range of statistical tests are applied to the ACORN generators, and their performance is compared with that of the linear congruential generators and the Chebyshev generators. The tests show the ACORN generators to be statistically superior to the Chebyshev generators, while being statistically similar to the linear congruential generators. However, the ACORN generators execute faster than linear congruential generators for the same statistical faithfulness. The main advantages of the ACORN generator are speed of execution, long period length, and simplicity of coding.