Bias, precision and accuracy of skewness and kurtosis estimators for frequently used continuous distributions

Several measures of skewness and kurtosis were proposed by Hogg (1974) in order to reduce the bias of conventional estimators when the distribution is non-normal. Here we conducted a Monte Carlo simulation study to compare the performance of conventional and Hogg's estimators, considering the most frequent continuous distributions used in health, education, and social sciences (gamma, lognormal and exponential distributions). In order to determine the bias, precision and accuracy of the skewness and kurtosis estimators for each distribution we calculated the relative bias, the coefficient of variation, and the scaled root mean square error. The effect of sample size on the estimators is also analyzed. In addition, a SAS program for calculating both conventional and Hogg's estimators is presented. The results indicated that for the non-normal distributions investigated, the estimators of skewness and kurtosis which best reflect the shape of the distribution are Hogg's estimators. It should also be noted that Hogg's estimators are not as affected by sample size as are conventional estimators

Predictive Modeling the Free Hydraulic Jumps Pressure through Advanced Statistical Methods

Pressure fluctuations beneath hydraulic jumps potentially endanger the stability of stilling basins. This paper deals with the mathematical modeling of the results of laboratory-scale experiments to estimate the extreme pressures. Experiments were carried out on a smooth stilling basin underneath free hydraulic jumps downstream of an Ogee spillway. From the probability distribution of measured instantaneous pressures, pressures with different probabilities could be determined. It was verified that maximum pressure fluctuations, and the negative pressures, are located at the positions near the spillway toe. Also, minimum pressure fluctuations are located at the downstream of hydraulic jumps. It was possible to assess the cumulative curves of pressure data related to the characteristic points along the basin, and different Froude numbers. To benchmark the results, the dimensionless forms of statistical parameters include mean pressures (P*m), the standard deviations of pressure fluctuations (σ*X), pressures with different non-exceedance probabilities (P*k%), and the statistical coefficient of the probability distribution (Nk%) were assessed. It was found that an existing method can be used to interpret the present data, and pressure distribution in similar conditions, by using a new second-order fractional relationships for σ*X, and Nk%. The values of the Nk% coefficient indicated a single mean value for each probability

Predicting student-teacher self-directed learning using intrinsic and extrinsic factors: a Theory of Planned Behavior adoption

IntroductionThis study set out to develop a model that illustrates the causal relationship between factors influencing Thai student-teacher self-directed learning (SDL). To achieve this, the authors analyzed and applied the Theory of Planned Behavior (TPB) to investigate the role of family support, teacher support, friend support, fellow students, and the university in influencing SDL.MethodsThe research used a sample of 468 student-teachers from five academic majors randomly selected from the King Mongkut’s Institute of Technology Ladkrabang (KMITL) Bachelor of Industrial Education Program during the 2021 academic year. The authors developed a questionnaire which was evaluated from both a panel of experts and a 30 student-teacher pilot test which found that item reliability was acceptable. LISREL 9.10 was used to analyze the data from the study’s structural equation model path analysis.ResultsThe results revealed that all the causal variables in the model positively influenced SDL, explaining the variance of influencing factors on SDL (R2) at 51%. SDL comprised five variables, when ranked in order of importance these were fellow students (FSt), teacher support (TS), family support (FS), friend support (FrS), and their university (Uni). The study also highlighted issues concerning each student-teacher’s learning time management ability and their perception of the university’s ability/willingness to allow each individual to choose their course, thus enhancing their SDL learning ability skills.DiscussionIt was speculated that some university educators even today perceive SDL as an adult education tool which they perceive is not appropriate at the university level. The authors also felt that for younger student-teachers that the COVID-19 medical emergency limited teacher/student/university interaction, thus contributing to student misconceptions about support availability. This study contributes significantly to the literature by investigating how TPB intrinsic and extrinsic factors impact a university student’s self-directed learning

The influence of technology readiness on technology acceptance in the South African mining industry

Mini Dissertation (MBA)--University of Pretoria, 2022.The South African mineral mining sector makes significant contributions to the local economy and participates in social initiatives that benefit employees and neighbouring communities. In recent years, volatile commodity prices, increased environmental and sustainability requirements, and deteriorating economic conditions have compelled global mining organisations to implement innovative technologies to address such challenges. Successful implementation of such technologies in the South African context is critical to ensure that the sector remains competitive and provides continued economic and social value. However, existing qualitative research concerning technology adoption within the sector has revealed that individuals have a resistive nature toward change and innovation. Therefore, this quantitative study investigated the influence of individuals’ technology predispositions and perceptions on usage intentions in the South African mining context. These facets were examined by extending the prevalent Technology Acceptance Model (TAM) with elements from the Technology Readiness Index (TRI). The influence of individual differences relating to chronological age, education level, and organisational roles was also investigated. Primary data was collected through non-probability snowball sampling of 150 respondents, and nonparametric statistical methods were used to determine the relationships between the TRI motivators, TRI inhibitors, TAM perceived usefulness (PU), and TAM usage intention (UI) constructs. It was found that there was a positive correlation between TRI motivators concerning PU and UI, with a converse relationship for the TRI inhibitors. There was a strong positive correlation between PU and UI, which confirmed the findings of several previous studies involving the TAM. There was no significant difference between groups of different chronological ages and organisational roles concerning UI, but there was a significant difference for individuals with different levels of education. Additionally, and importantly, it was found that the respondents primarily held a positive perception and linked inclination towards adoption intentions, which contradicted the findings within the existing literature. The results also indicated a high degree of predictability concerning adoption based on individuals’ perceptions. Stakeholders and managers looking to technology to solve business challenges should consider these perceptions to ensure successful implementation.pt23Gordon Institute of Business Science (GIBS)MBAUnrestricte

Exploring the impact of economic hardship on the development of self-esteem

Doctor of PhilosophyDepartment of Human Ecology-Personal Financial PlanningMegan McCoyThis study examines the impact of economic hardship on self-esteem development using the family stress model (Conger et al., 1990) as a theoretical framework. Self-esteem serves as an indicator of current well-being and future success for both researchers and practitioners. This study focuses on understanding economic hardship's impact on self-esteem development through family dynamics and processes conceptualized by the family stress model. Using the National Longitudinal Study of Adolescent to Adult Health (ADD Health), a sample of 730 respondents is examined through structural equation modeling to assess economic hardship's impact on self-esteem development. The results indicate that while economic hardship has no significant effect on self-esteem development in this sample, the role of mothers has a significant and long-term impact on self-esteem in emerging adulthood. Moreover, when considering the effects that gender has on self-esteem development via moderation, neither male nor female emerging adults experienced differing effects between disrupted parenting and self-esteem. While researchers should continue to explore more research to understand the impact of economic hardship on self-esteem, the parent-to-adolescent relationship significantly impacts self-esteem development. Financial planners, counselors, and therapists are focused on wealth accumulation, maximization, and enjoyment for their clients. Their understanding of childhood experiences of economic hardship on self-esteem via family dynamics and processes helps them understand early indicators of academic and job performance, wealth accumulation, financial risk-taking, and seeking financial advice. To support their clients and the next generation, financial professionals' focus can remain and expand on family dynamics and processes that have affected and continue to affect financial wellness and decision-making and focus less on the economic background and previous economic hardship experienced by their family