An unresolved issue exists in the study of mental ability: which aspect of cognition is responsible for the emergence of psychometric “g” (Spearman, 1904, 1927), a general factor that predicts performance in all kinds of cognitive tasks and many important life outcomes? On the basis of themes present in the literature on fluid intelligence (Chapter 1), this thesis explores the relative contributions of processing, storage, and task modelling demands to the recruitment of g in task performance. Six experiments are presented which employed two computer-based tasks. The tasks were designed such that the level of demand for processing and storage was separated and manipulated in order to establish their relationship to scores on a standard test of g. Task manipulations were implemented in the context of varying the number of distinct verbal chunks in which task instructions were presented, whilst controlling for the presented amount of operative task-relevant information. The findings showed that the recruitment of g in task performance was strengthened by the presence (versus the absence) of a requirement to inhibit a prepotent response tendency (Experiments 1, 2, and 3), and by the presence of requirements to inhibit a prepared response and to maintain and update information in working memory (Experiments 4 and 5). However, these effects were observed only when task instructions were presented as four (and not as two) distinct rules. Additional findings showed that reconceptualisation of task requirements—that is, flexibly imposing order on a complex set of instructions thus reducing the number of distinct verbal chunks—was dependent on performance on the test of Spearman’s g (Experiments 3 through 6). These findings are deemed consistent with a task conceptualisation theory of g, with real-time execution demand, particularly inhibition, posing as a risk factor for the recruitment of g only when task requirements are maintained in mind as a relatively large number of chunks or rules.

The research aims to investigate the relationship between economic freedom, political freedom and economic growth. The Arab Spring placed renewed interest on the topic of freedom, yet current economic conditions seemingly contradicted the established theory. The largest free economies were being outperformed by those with less political and economic freedom.Three objectives were specified to answer the research question. The first objective aimed to determine the association between economic freedom, political freedom and economic growth, for which Spearman’s correlation was used. The second objective aimed to investigate causal relationships between the variables, for which Granger’s causality was employed. The third objective aimed to examine complex relationships between the variables, for which vector autoregression was used.Economic growth was weakly correlated with the independent variables. Civil liberties, political rights and economic freedom, however, had strong correlations with each other. Economic freedom and economic growth had bi-directional Granger-causality. Political rights Granger-caused economic freedom whilst civil liberties Granger-caused political rights and economic freedom. Using vector autoregression, the model consisting of economic growth, economic freedom and civil liberties had the greatest explanatory power towards economic growth. Existing theory therefore remains valid: political freedom enhances economic freedom, which, in turn, enhances economic growth.The relationship between economic freedom, political freedom and economic growth / Dissertation (MBA)--University of Pretoria, 2012. / Gordon Institute of Business Science (GIBS) / unrestricted

As technology development is advancing almost exponentially, it has since touched almost every aspect in our lives, from work to recreation. Therefore, in view of the extent to which technology is integrated in modern socio-economic settings, this study undertook to investigate South African schools readiness to integrate ICT. The following research questions were investigated: What is the relationship between the importance of ICT use for 21st Century Skill Development and obstructions hindering ICT goals in the light of currently available Infrastructure in South African schools? What is the relationship between the importance of ICT use for 21st Century Skill Development and obstructions hindering ICT goals in the light of currently available Human Resources in South African schools? A Spearman’s rho correlation was calculated, using SITES 2006 data obtained from the Principal Questionnaire (Brese & Carstens, 2009). It was found that all of the influencing factors, pertaining to both Infrastructure and Human Resources, showed a weak, to very weak negative correlation with the ICT goals under question. This means that, though the relationship is not strong, the influencing factors are hindering schools from reaching ICT goals for 21st Century Skills Development. / Dissertation (MEd)--University of Pretoria, 2013. / gm2014 / Science, Mathematics and Technology Education / unrestricted

The objective of this thesis is to analyse theconnection between test results and field claims of ECUs (electronic controlunits) at Scania in order to improve the acceptance criteria and evaluatesoftware testing strategies. The connection is examined through computation ofdifferent measures of dependencies such as the Pearson’s correlation, Spearman’srank correlation and Kendall’s tau. The correlations are computed from testresults in different ECU projects and considered in a predictive model based onlogistic regression. Numerical results indicate a weak connection between testresults and field claims. This is partly due to insufficient number of ECUprojects and the lack of traceability of field claims and test results. Themain conclusion confirms the present software testing strategy. Continuoussoftware release and testing results in a lower field claim and thus a betterproduct.

This thesis examined the sensitivity of the EQ-5D-5L instrument in measuring health-related quality of life (HRQoL) among patients with persistent symptoms following COVID-19, including fatigue, memory and concentration problems, and dyspnea. Additionally, it was analyzed whether adding these symptoms to the EQ-5D-5L improved the explained variance for HRQoL. Patients from Uppsala University Hospital, Sweden, answered a survey that included questions on five dimensions of health represented by the EQ-5D-5L and an additional question on general health score called EQ-VAS. Multiple linear regression, Spearman’s rank correlation coefficient, and Least Absolute Shrinkage and Selection Operator (LASSO) were used to examine the sensitivity of the EQ-5D-5L. For the explanatory analysis, the Adjusted 𝑅2 was used to evaluate explanatory power with and without the presence of the symptoms. The results showed that the EQ-5D-5L dimensions explained a moderate proportion of the variance for fatigue and memory/concentration problems and a weak proportion for dyspnea. The explanatory analysis provided findings that fatigue significantly improved the explained variance of EQ-VAS by 5.5%, adding memory/concentration problems only improved it marginally, and adding dyspnea was non-significant. Additionally, strong to moderate correlations between fatigue and memory/concentration problems were found with multiple dimensions of the EQ-5D-5L. These findings suggest that the EQ-5D-5L instrument may be a valuable tool in assessing HRQoL in patients with persistent COVID-19 symptoms and that adding fatigue to the EQ-5D-5L could be beneficial for improving explanatory power to HRQoL in patients suffering from infectious disease. / COMBAT post-covid

Résumé : Il est bien connu que les lois marginales d'un vecteur aléatoire ne suffisent pas à caractériser sa distribution. Lorsque les lois marginales du vecteur aléatoire sont continues, le théorème de Sklar garantit l'existence et l'unicité d'une fonction appelée copule, caractérisant la dépendance entre les composantes du vecteur. La loi du vecteur aléatoire est parfaitement définie par la donnée des lois marginales et de la copule. Dans ce travail de thèse, nous proposons deux tests non paramétriques de détection de ruptures dans la distribution d’observations multivariées, particulièrement sensibles à des changements dans la copule des observations. Ils améliorent tous deux des propositions récentes et donnent lieu à des tests plus puissants que leurs prédécesseurs pour des classes d’alternatives pertinentes. Des simulations de Monte Carlo illustrent les performances de ces tests sur des échantillons de taille modérée. Le premier test est fondé sur une statistique à la Cramér-von Mises construite à partir du processus de copule empirique séquentiel. Une procédure de rééchantillonnage à base de multiplicateurs est proposée pour la statistique de test ; sa validité asymptotique sous l’hypothèse nulle est démontrée sous des conditions de mélange fort sur les données. Le second test se focalise sur la détection d’un changement dans le rho de Spearman multivarié des observations. Bien que moins général, il présente de meilleurs résultats en terme de puissance que le premier test pour les alternatives caractérisées par un changement dans le rho de Spearman. Deux stratégies de calcul de la valeur p sont comparées théoriquement et empiriquement : l’une utilise un rééchantillonnage de la statistique, l’autre est fondée sur une estimation de la loi limite de la statistique de test. // Abstract : It is very well-known that the marginal distributions of a random vector do not characterize the distribution of the random vector. When the marginal distributions are continuous, the work of Sklar ensures the existence and uniqueness of a function called copula which can be regarded as capturing the dependence between the components of the random vector. The cumulative distribution function of the vector can then be rewritten using only the copula and the marginal cumulative distribution functions. In this work, we propose two non-parametric tests for change-point detection, particularly sensitive to changes in the copula of multivariate time series. They improve on recent propositions and are more powerful for relevant alternatives involving a change in the copula. The finite-sample behavior of these tests is investigated through Monte Carlo experiments. The first test is based on a Cramér-von Mises statistic and on the sequential empirical copula process. A multiplier resampling scheme is suggested and its asymptotic validity under the null hypothesis is demonstrated under strong mixing conditions. The second test focuses on the detection of a change in Spearman’s rho. Monte Carlo simulations reveal that this test is more powerful than the first test for alternatives characterized by a change in Spearman’s rho. Two approaches to compute approximate p-values for the test are studied empirically and theoretically. The first one is based on resampling, the second one consists of estimating the asymptotic null distribution of the test statistic.

本研究的主要目的，在於探討中國大陸的得獎基金之績效持續性是否存在？本研究利用晨星與理柏兩家國際專業評級機構於2004年至2012年所頒發的中國大陸得獎基金為研究樣本（前者的樣本為41檔基金，後者的樣本為53檔基金），資料來源分別為晨星資訊（深圳）有限公司及新浪網。在分別採用累計淨值報酬率、Sharpe指標作為績效衡量指標，並使用Spearman等級相關檢定、績效二分法與迴歸分析，以驗證中國大陸得獎基金在頒發前後不同期間的績效表現是否具有持續性。研究結果發現，前兩種檢定方法皆呈現基金績效在短期（三個月及六個月）具有持續性，而在長期甚至出現績效反轉的現象。而迴歸模型分析的主要發現為，在控制其他變數後，獲得晨星中國基金獎之基金在短期才具持續性，在一年時出現績效反轉。而獲得理柏中國基金奬之基金，在六個月的評估期間就可能出現績效反轉的現象。 / The purpose of this study is to investigate whether the persistence of awarded funds’ performance exist in China. This study employs awarded funds of MorningStar award and Lipper award in China as the sample provided by Morningstar website in China and Sina website. Using accumulated rate of return and Sharpe index as the measurements of awarded funds’ performance and Spearman’s rank correlation coefficient, two-way table constructed by Goetzmann and Ibbotson (1994) and regression analysis as methodologies to analyze this issue in different before-and-after periods, the primary finding of this study is that the former two methodologies show that the performance persistence of awarded funds exist only in three- and six-month periods, and performance reversal appears in the long-run. According to regression analysis, this study suggests that MorningStar awarded funds might have persistent performance in the short-run, but performance reversal after 1-year period. However, Lipper awarded funds do not have persistent performance, but performance reversal after six-month period.

The purpose of this study is to investigate physics teachers’ (TPCK) and their learners’ achievement in electricity. A purposive sample of 42 Grade 11 physics teachers and 1423 learners participated in the study. An explanatory mixed method research design was employed in the study to collect data. A survey questionnaire (PTTPCKQ), consisting of six-point Likert scale questions, was answered by participating teachers. Similarly, their learners responded to a confirmatory questionnaire (LCPTTPCKQ). The learners also responded to the Electricity Learning Confirmatory Questionnaire (LELCQ) and wrote an achievement test called Learner Electricity Achievement Test (LEAT). The data collected was analysed both quantitatively and qualitatively. Quantitatively, it was found that a positive, statistically significant relationship existed between physics teachers’ experience and their learners’ achievement [Spearman’s rho (42) = .39, p = .011] as well as physics teachers’ TPCK and their qualifications [Spearman’s rho (42) = .33, p = .003]. There was also a positive statistical relationship between physics teachers’ TPCK and learner achievement, yet this was not statistically significant. There were positive, statistically significant relationships between all the constructs of the physics teachers’ TPCK and their TPCK from the analysis of the PTTPCKQ. There were positive statistically significant relationships between all the constructs of the physics teachers’ TPCK and their TPCK, according to the analysis of the LCPTTPCKQ. Furthermore, comparing the learners’ responses on the LCTTPCKQ and their teachers’ responses on the PTTPCKQ, it was found that both learners and teachers provided similar responses for all the constructs of TPCK except TCK. Qualitative data analysis further revealed that the technologies used by these teachers were PhET Simulations, YouTube Videos, Power Point Presentations, Interactive White Boards, and Mindset Videos. Finally, between 12.9% and 5.2% of the learners reported that their teachers had neglected to teach some sections of the electricity in the curriculum. / Mathematical Sciences / Ph. D. (Mathematics, Science and Technology Education)

Reading and mathematics are two essential subjects for academic success and cognitive development. Several studies show a correlation between the reading ability and mathematical ability of pupils (Korpershoek et al., 2015; Ní Ríordáin & O’Donoghue, 2009; Reikerås, 2006; Walker et al., 2008). The didactical part of this thesis presents a study investigating a correlation between reading ability and mathematical ability among pupils in upper secondary schools in Sweden. This study collaborated with Lexplore AB to use machine learning and eye-tracking to measure reading ability. Mathematical ability was measured with Mathematics 1c grades and Stockholmsprovet, which is a diagnostic mathematics test. Although no correlation was found, there are several insights about selection and measures following the result that may improve future studies on the subject. This thesis finds that the result could have been affected by a biased selection of the participants. This thesis also suggests that the measure through machine learning and eye-tracking used in the study may not fully capture the concept of reading ability as defined in previous studies. The technological aspect of this thesis focuses on modifying and improving the model used to calculate users’ reading ability scores. As the model’s estimation tends to plateau after the fifth year of compulsory school, the study aims to maintain the same level of progression observed before this point. Previous research indicates that silent reading, being unconstrained by vocalization, is faster than reading aloud. To address this progression flattening, a grid search algorithm was employed to adjust hyperparameters and assign appropriate weight to silent and aloud reading. The findings emphasize that reading aloud should be prioritized in the weighted average and the corresponding hyperparameters adjusted accordingly. Furthermore, gathering more data for older pupils can improve the machine learning model by accounting for individual reading strategies. Introducing different word complexity factors can also enhance the model’s performance. / Läsning och matematik är två avgörande ämnen för akademisk framgång och kognitiv utveckling. Flera studier visar på ett samband mellan elevers läsförmåga och matematiska förmåga (Korpershoek et al., 2015; Ní Ríordáin & O’Donoghue, 2009; Reikerås, 2006; Walker et al., 2008). Den didaktiska delen av denna rapport presenterar en studie som undersöker sambandet mellan läsförmåga och matematisk förmåga hos elever på gymnasiet i Sverige. Studien samarbetade med Lexplore AB för att använda maskininlärning och ögonspårning för att mäta läsförmåga. Matematisk förmåga mättes genom matematikbetyg och Stockholms provet, som är ett diagnostiskt matematiktest. Trotsatt inget samband hittades uppges insikter om urvalet och åtgärder som kan förbättra framtida studier i ämnet. Rapporten konstaterar att resultatet kan ha påverkats avett sned vridet urval av deltagare. Dessutom föreslår rapporten att mätningen genom maskininlärning och ögonspårning som användes i studien kanske inte helt fångar upp begreppet läsförmåga som används i tidigare studier. Teknikdelen av denna rapport fokuserar på att modifiera och förbättra modellen som används för att beräkna användarnas läsförmågepoäng. Eftersom modellens uppskattning tenderar att avplattas efter femte året i grundskola, syftar studien till att bibehålla samma nivå av progression som observerats före denna punkt. Tidigare forskning indikerar att tyst läsning, som inte begränsas av att uttala orden, är snabbare än högläsning. För att adressera denna avplattning av progression användes en rutnätssöknings-algoritm för att justera hyperparametrar och tilldela rätt viktning åt tyst läsning. Resultaten betonar att högläsning bör prioriteras i viktade medelvärdet och att motsvarande justeringar av hyperparametrar bör implementeras. Dessutom kan insamling av mer data för äldre elever förbättra maskininlärningsmodellen genom att ta hänsyn till individuella lässtrategier. Införandet av olika faktorer för textkomplexitet kan också förbättra modellens prestanda.

The potential for a gastroenteritis outbreak in a post-earthquake environment may increase because of compromised infrastructure services, contaminated liquefaction (lateral spreading and surface ejecta), and the presence of gastroenteritis agents in the drinking water network. A population in a post-earthquake environment might be seriously affected by gastroenteritis because it has a short incubation period (about 10 hours). The potential for a gastroenteritis outbreak in a post-earthquake environment may increase because of compromised infrastructure services, contaminated liquefaction (lateral spreading and surface ejecta), and the presence of gastroenteritis agents in the drinking water network. A population in a post-earthquake environment might be seriously affected by gastroenteritis because it has a short incubation period (about 10 hours). The aim of this multidisciplinary research was to retrospectively analyse the gastroenteritis prevalence following the February 22, 2011 earthquake in Christchurch. The first focus was to assess whether earthquake-induced infrastructure damage, liquefaction, and gastroenteritis agents spatially explained the recorded gastroenteritis cases over the period of 35 days following the February 22, 2011 earthquake in Christchurch. The gastroenteritis agents considered in this study were Escherichia coli found in the drinking water supply (MPN/100mL) and Non-Compliant Free Associated Chlorine (FAC-NC) (less than <0.02mg/L). The second focus was the protocols that averted a gastroenteritis outbreak at three Emergency Centres (ECs): Burnside High School Emergency Centre (BEC); Cowles Stadium Emergency Centre (CEC); and Linwood High School Emergency Centre (LEC). Using a mixed-method approach, gastroenteritis point prevalence and the considered factors were quantitatively analysed. The qualitative analysis involved interviewing 30 EC staff members. The data was evaluated by adopting the Grounded Theory (GT) approach. Spatial analysis of considered factors showed that highly damaged CAUs were statistically clustered as demonstrated by Moran’s I statistic and hot spot analysis. Further modelling showed that gastroenteritis point prevalence clustering could not be fully explained by infrastructure damage alone, and other factors influenced the recorded gastroenteritis point prevalence. However, the results of this research suggest that there was a tenuous, indirect relationship between recorded gastroenteritis point prevalence and the considered factors: earthquake-induced infrastructure damage, liquefaction and FAC-NC. Two ECs were opened as part of the post-earthquake response in areas with severe infrastructure damage and liquefaction (BEC and CEC). The third EC (CEC) provided important lessons that were learnt from the previous September 4, 2010 earthquake, and implemented after the February 22, 2011 earthquake. Two types of interwoven themes identified: direct and indirect. The direct themes were preventive protocols and indirect themes included type of EC building (school or a sports stadium), and EC staff. The main limitations of the research were Modifiable Areal Units (MAUP), data detection, and memory loss. This research provides a practical method that can be adapted to assess gastroenteritis risk in a post-earthquake environment. Thus, this mixed method approach can be used in other disaster contexts to study gastroenteritis prevalence, and can serve as an appendage to the existing framework for assessing infectious diseases. Furthermore, the lessons learnt from qualitative analysis can inform the current infectious disease management plans, designed for a post-disaster response in New Zealand and internationally Using a mixed-method approach, gastroenteritis point prevalence and the considered factors were quantitatively analysed. A damage profile was created by amalgamating different types of damage for the considered factors for each Census Area Unit (CAU) in Christchurch. The damage profile enabled the application of a variety of statistical methods which included Moran’s I , Hot Spot (HS) analysis, Spearman’s Rho, and Besag–York–Mollié Model using a range of software. The qualitative analysis involved interviewing 30 EC staff members. The data was evaluated by adopting the Grounded Theory (GT) approach. Spatial analysis of considered factors showed that highly damaged CAUs were statistically clustered as demonstrated by Moran’s I statistic and hot spot analysis. Further modelling showed that gastroenteritis point prevalence clustering could not be fully explained by infrastructure damage alone, and other factors influenced the recorded gastroenteritis point prevalence. However, the results of this research suggest that there was a tenuous, indirect relationship between recorded gastroenteritis point prevalence and the considered factors: earthquake-induced infrastructure damage, liquefaction and FAC-NC. Two ECs were opened as part of the post-earthquake response in areas with severe infrastructure damage and liquefaction (BEC and CEC). The third EC (CEC) provided important lessons that were learnt from the previous September 4, 2010 earthquake, and implemented after the February 22, 2011 earthquake. The ECs were selected to represent the Christchurch area, and were situated where potential for gastroenteritis was high. BEC represented the western side of Christchurch; whilst, CEC and LEC represented the eastern side, where the potential for gastroenteritis was high according to the outputs of the quantitative spatial modelling. Qualitative analysis from the interviews at the ECs revealed that evacuees were arriving at the ECs with gastroenteritis-like symptoms. Participants believed that those symptoms did not originate at the ECs. Two types of interwoven themes identified: direct and indirect. The direct themes were preventive protocols that included prolific use of hand sanitisers; surveillance; and the services offered. Indirect themes included the EC layout, type of EC building (school or a sports stadium), and EC staff. Indirect themes governed the quality and sustainability of the direct themes implemented, which in turn averted gastroenteritis outbreaks at the ECs. The main limitations of the research were Modifiable Areal Units (MAUP), data detection, and memory loss. It was concluded that gastroenteritis point prevalence following the February 22, 2011 earthquake could not be solely explained by earthquake-induced infrastructure damage, liquefaction, and gastroenteritis causative agents alone. However, this research provides a practical method that can be adapted to assess gastroenteritis risk in a post-earthquake environment. Creating a damage profile for each CAU and using spatial data analysis can isolate vulnerable areas, and qualitative data analysis provides localised information. Thus, this mixed method approach can be used in other disaster contexts to study gastroenteritis prevalence, and can serve as an appendage to the existing framework for assessing infectious diseases. Furthermore, the lessons learnt from qualitative analysis can inform the current infectious disease management plans, designed for a post-disaster response in New Zealand and internationally.