Quality of multiple choice questions in a numerical and statistical methods course

The quality control of written examination is very important in the teaching and learning process of any course. In educational assessment contexts, Item Response Theory (IRT) has been applied to measure the quality of a test in areas of knowledge like medicine, psychology, and social sciences, and its interest has been growing in other topics as well. Based on statistical models for the probability of an individual answering a question correctly, IRT can be addressed to measure examiners’ ability in an assessment test and to estimate difficulty and discrimination levels of each item in the test. In this work, IRT is applied to Numerical and Statistical Methods course to measure the quality of tests based on Multiple Choice Questions (MCQ). The present study focuses on three school years, namely 2015, 2016 and 2017, more specifically on the 1st semester of the 2nd year of the degree course. It has involved more than 300 students in each year, and it points out questions (also called items) from some chapters of the program that were evaluated through MCQ. Emphasis is given on the range of item difficulty and item discrimination parameters, estimated by IRT methodology, for each question in those exams. We show where each partial exam explores ability levels: at a passing point or at more demanding levels. After the application of IRT to each test, which was composed of eight questions, we got 48 item difficulty and item discrimination parameters. The application of standard boxplots shows few atypical responses from students in terms of extremal values of difficulty and discrimination, which corresponds to MCQ that deserve further attention. We have concluded that the vast majority of questions are well posed considering that they are designed to focus on the cut-off point (passing/not passing). A proposed reflection, about the learned benefits from ‘good’ outliers and possible causes for those ‘bad’ items, suggests future improvements to classes, study materials and exams.publishe

Correcting for Sampling Problems in PISA and the Improvement in Portuguese Students’ Performance

PISA uses a complex sampling procedure based on stratification variables chosen by the participating countries’ authorities. In this paper we analyse the representativeness of the samples used in terms of the distribution of students per grade and track of studies for Portugal. For the three exam years under analysis (2006, 2009 and 2012) a meaningful bias between the effective student distribution and PISA samples was found. We provide recalculated PISA scores that correct for the sample bias. We find that from 2009 to 2012, contrary to the stagnation denoted in the PISA results, the recalculated scores show an improvement in the Portuguese student performance. We also decompose the evolution of the scores into two effects: (i) change in the student population distribution by grade and track, and type of school; and (ii) evolution in the performance of each type of student. The results show that for the whole period the evolution of the students’ scores is the main driver of the increase in PISA results, with the change in the population structure playing a weaker role. Although we focus on the Portuguese case, similar problems of representativeness are expected to arise in other countries with high retention rates, affecting the grade of study of 15-year-olds.N/

AVALIAÇÃO DA SEGURANÇA DE TRABALHADORES EM SERRALHERIA NO MUNICÍPIO DE CAÇAPAVA DO SUL

A segurança no trabalho é importante para prevenir acidentes e garantir um bom ambiente para todos os trabalhadores. Através de profissionais qualificados na área como os engenheiros em segurança do trabalho e os técnicos em segurança no trabalho, é possível diagnosticar irregularidades que possam comprometer a segurança dos funcionários de uma determinada empresa. É necessário que a empresa conheça e respeite as leis trabalhistas e as normas regulamentadoras que regem qualquer tipo de atividade que comprometa ou ponha em risco a vida de seus funcionários. O presente trabalho tem por objetivo listar os principais fatores de risco em uma pequena empresa do ramo de serralheria localizada na cidade de Caçapava do Sul, RS, e ainda verificar se está se encontra em conformidade ou não conformidade com as NRs estabelecidas para atividade serralheira

ANÁLISE DA GESTÃO E CONTROLE AMBIENTAL EM POSTO DE COMBUSTÍVEL EM CAÇAPAVA DO SUL -RS

Em virtude de um possível desequilíbrio ambiental, as empresas de postos e abastecimento de combustível devem conter um sistema de planejamento ambiental na empresa. Esse segmento compõe atividades que apresentam um alto potencial de poluição e assim são considerados pela legislação ambiental brasileira. Tal fato se dá pelos aspectos relacionados às suas atividades e ao potencial perigo ao meio ambiente. Devido a isso, o objetivo do trabalho foi identificar e descrever as relações do posto de combustível com o meio ambiente, estudar as medidas de gestão ambiental que estão sendo adotadas e as que devem ser adotadas pelo segmento. Para o desenvolvimento do estudo, foram levantados dados iniciais, em um Posto de Combustível de Caçapava do Sul/RS, para após preenchimento do formulário do FMEA. Também foi aplicado um questionário-base do ISP e em seguida realizada a elaboração de um cronograma de ações. Os resultados revelaram que a empresa interage com o meio ambiente quando utiliza a água como insumo nas atividades desenvolvidas e pela geração de resíduos como: óleo queimado, lodo tóxico, embalagens de lubrificantes e efluentes líquidos. Constatou-se, ainda, que estes resíduos são recolhidos por empresa especializada, porém os efluentes do local não são devidamente tratados, sendo assim despejados em esgoto comum. Portanto, foi possível verificar que o empreendimento conta com algumas medidas de gestão ambiental, entretanto não são suficientes para esse tipo de atividade

Ten-year survival of patients undergoing coronary angioplasty with first-generation sirolimus-eluting stents and bare-metal stents

Introduction: Compared to bare-metal stents (BMS), drug-eluting stents reduce stent restenosis and improve subsequent revascularization rates. The impact on patients’ survival has been the subject of debate. Objective: To assess the long-term (10-year) survival of patients undergoing percutaneous coronary intervention (PCI) with first-generation sirolimus-eluting stents (SES) in comparison with BMS. Methods: In a single-center registry, 600 consecutive patients who underwent successful PCI with SES between April 2002 and February 2003 were compared to 594 patients who underwent PCI with BMS between January 2002 and April 2002, just before the introduction of SES. Clinical and procedural data were collected at the time of intervention and 10-year survival status was assessed via the national life status database. Results: All baseline characteristics were similar between groups except for smaller stent diameter (2.84±0.38 vs. 3.19±0.49 mm; p<0.001), greater stent length (18.50±8.2 vs. 15.96±6.10 mm; p<0.001) and higher number of stents per patient (1.95 vs. 1.46, p<0.001) in the SES group. Overall five- and 10-year all-cause mortality was 9.6% (n=110) and 22.7% (n=272), respectively. The adjusted HR for 10-year mortality in patients undergoing PCI with SES was 0.74 (95% CI 0.58-0.94; p=0.013), corresponding to a relative risk reduction of 19.8%. Other than PCI with BMS, older age, chronic kidney disease, chronic obstructive pulmonary disease and lower ejection fraction were independent predictors of 10-year mortality. Conclusion: To date, this is the longest follow-up study ever showing a potential survival benefit of first-generation sirolimus-eluting stents versus bare-metal stents, supporting prior observations on their sustained efficacy and safety relative to contemporary BMS.publishersversionpublishe

Environmental and biological controls of Mg/Ca, Sr/Ca and Mn/Ca ratios in the shells of the bivalves Pinna nobilis, Mytilus edulis and Pecten maximus : implications for palaeo-environmental reconstructions

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