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Given the limitations of frequentist method for null hypothesis significance testing, different authors recommend alternatives such as Bayesian inference. A poor understanding of both statistical frameworks is common among clinicians. The present is a gentle narrative review of the frequentist and Bayesian methods intended for physicians not familiar with mathematics. The frequentist p-value is the probability of finding a value equal to or higher than that observed in a study, assuming that the null hypothesis (H0) is true. The H0 is rejected or not based on a p threshold of 0.05, and this dichotomous approach does not express the probability that the alternative hypothesis (H1) is true. The Bayesian method calculates the probability of H1 and H0 considering prior odds and the Bayes factor (Bf). Prior odds are the researcher's belief about the probability of H1, and the Bf quantifies how consistent the data is concerning H1 and H0. The Bayesian prediction is not dichotomous but is expressed in continuous scales of the Bf and of the posterior odds. The JASP software enables the performance of both frequentist and Bayesian analyses in a friendly and intuitive way, and its application is displayed at the end of the paper. In conclusion, the frequentist method expresses how consistent the data is with H0 in terms of p-values, with no consideration of the probability of H1. The Bayesian model is a more comprehensive prediction because it quantifies in continuous scales the evidence for H1 versus H0 in terms of the Bf and the

Dadas las limitaciones del método de significancia frecuentista basado en la hipótesis nula, diferentes autores recomiendan alternativas como la inferencia bayesiana. Es común entre los médicos una comprensión deficiente de ambos marcos estadísticos. Esta es una revisión narrativa amigable de los métodos frecuentista y bayesiano dirigida quienes no están familiarizados con las matemáticas. El valor de p frecuentista es la probabilidad de encontrar un valor igual o superior al observado en un estudio, asumiendo que la hipótesis nula (H0) es cierta. La H0 se rechaza o no con base en un umbral p de 0.05, y este enfoque dicotómico no expresa la probabilidad de que la hipótesis alternativa (H1) sea verdadera. El método bayesiano calcula la probabilidad de H1 y H0 considerando las probabilidades a priori y el factor de Bayes (fB). Las probabilidades a priori son la creencia del investigador sobre la probabilidad de H1, y el fB cuantifica cuán consistentes son los datos con respecto a H1 y H0. La predicción bayesiana no es dicotómica, sino que se expresa en escalas continuas del fB y de las probabilidades a posteriori. El programa JASP permite realizar análisis frecuentista y bayesiano de una forma simple e intuitiva, y su aplicación se muestra al final del documento. En conclusión, el método frecuentista expresa cuán consistentes son los datos con H0 en términos de valores p, sin considerar la probabilidad de H1. El modelo bayesiano es una predicción más completa porque cuantifica en escalas continuas la evidencia de H1 versus H0 en términos del fB y de las probabilidades a posteriori.

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Abstract Background: Treatment time in the emergency room for acute myocardial infarction is very important and can be life-saving if one understands the importance of a patient's chest pain. Objetice: The aim of this study is to evaluate how much patients entering the emergency room due to acute myocardial infection (AMI) know about chest pain and thrombolytic therapy. Materials and Methods: One hundred fifty patients (126 males,14 females) from three different institutes with complaints of chest pain were randomly chosen to participate in this study. The mean age of the patients was 55.4 ± 11.2 years (71+33). Patients were asked to fill out a questionnaire consisting of 70 questions within the first seven days. All differences in categorical variables were computed using the χ2-test and Fisher Exact test. A two-tailed hypothesis was used in all statistical evaluations, and p<0.05 was considered significant. Results: It was observed that 17% of the patients came to the hospital within the first 30 minutes; 18.3% of them came to the hospital between 30 minutes and 1 hour; 27.5% of them came to the hospital between 1 hour and 3 hours; and 21.4% of them came to the hospital more than 6 hours after symptoms began. It was also observed that 68% of the patients were not aware of the AMI, and 96% of them had no prior knowledge of antithrombolytic therapy. Conclusion: Because the majority of the patients did not have enough information about AMI, a training program should be implemented to ensure that people to come to the hospital earlier. (Int J Cardiovasc Sci. 2021; [online].ahead print, PP.0-0)

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El factor de Bayes resulta una prueba recomendable para la comprobación de las hipótesis esta-dísticas atendiendo al estado de los p valores, empleando la escala de clasificación de Jeffreys preferiblemente

The Bayes factor is a recommended test for the verification of statistical hypotheses taking into account the state of the p values, preferably using the Jeffreys classification scale.

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Abstract Objectives: to develop and analyze the psychometric properties of a questionnaire to assess community health workers' knowledge on breastfeeding. Methods: this is a methodological study for the development of an instrument and analysis of validity and reliability. For the elaboration of items and identification of dimensions, a literature review was conducted. The items were submitted to the evaluation of a committee of judges, for apparent and content analysis. Construct validation was conducted through hypothesis test, with the participation of 282 community health workers and 19 pediatricians and obstetric nurses. For analysis and comparison of scores, the Mann-Whitney U test was used, assuming a significance level of 5%. Reliability was assessed using Cronbach's alpha coefficient and temporal consistency of the instrument was assessed using test-retest and Kappa analysis. Results: the final instrument presented a favorable opinion from the committee of judges. The hypothesis test showed that the questionnaire has discriminatory power to assess professionals with a higher level of knowledge (p<0.001). The Kappa test revealed that 63% of the items showed substantive to almost perfect agreement. The 32-item questionnaire showed a Cronbach's alpha of 0.794. Conclusion: the instrument developed was valid and reliable, allowing effective measurement of community health workers' knowledge on breastfeeding.

Resumo Objetivos: elaborar e analisar propriedades psicométricas de um questionário para avaliação do conhecimento de agentes comunitários de saúde sobre amamentação. Métodos: trata-se de estudo metodológico de elaboração de instrumento e análise de validade e confiabilidade. Para a elaboração dos itens e identificação das dimensões, realizou-se revisão da literatura. Os itens foram submetidos à apreciação de comitê de juízes, para análise aparente e de conteúdo. A validação de construto foi conduzida pelo teste de hipóteses, com participação de 282 agentes comunitários de saúde e 19 pediatras e enfermeiras obstetras. Para comparação dos escores, utilizou-se o teste U de Mann-Whitney, assumindo-se um nível de significância de 5%. A confiabilidade foi aferida por meio do coeficiente alfa de Cronbach e a consistência temporal do instrumento por meio do teste-reteste e análise de Kappa. Resultados: o instrumento final apresentou parecer favorável do comitê de juízes. O teste de hipóteses evidenciou que o instrumento tem poder discriminatório para aferir profissionais com maior nível de conhecimento (p<0,001). O teste Kappa revelou que 63% dos itens apresentaram concordância de substantiva a quase perfeita. O questionário, com 32 itens, apresentou um alfa de Cronbach de 0,794. Conclusão: o instrumento apresentou-se válido e confiável que permitirá mensurar de forma eficaz o conhecimento de agentes comunitários de saúde sobre amamentação.

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Os testes de hipótese são amplamente empregados para análise de dados na área de ciência do esporte. Porém, existe um questionamento em relação a utilização desse método e a comunidade científica ainda procura soluções mais adequadas para a análise dos dados. De fato, esse tipo de análise não permite uma interpretação prática das mudanças observadas ao longo do tempo. Por conta disso, o cálculo da "in ferência baseada em magnitude" (IBM) vem sendo cada vez mais utilizado por pesquisadores e analistas de desempenho. Em uma perspectiva aplicada, a IBM permite avaliar a probabilidade de se encontrar diferenças relevantes (i.e., meaningful differences) nas variáveis investigadas. Da mesma forma, a IBM permite examinar com precisão as variações individuais e importantes no desempenho esportivo. O objetivo desse ponto de vista é apresentar e discutir a aplicação da IBM a partir das análises individuais. Para tanto o trabalho aborda os seguintes temas: 1) utilização da análise de dados no "mundo real"; 2) inferência baseada em magnitude: conceitos básicos; 3) aplicando a IBM no contexto do esporte; 4) classificações qualitativas com base nas mudanças observadas; 5) formas de se obter a mínima mudança válida importante e o erro típico; 6) análise e interpretação dos dados. Esperamos que o conteúdo apresentado encoraje pesquisadores e profissionais do esporte a implementar esse novo método de análise em suas rotinas diárias e, ao mesmo tempo, lhes auxilie na interpretação dos dados provenientes das avaliações e testes de desempenho.(AU)

Null hypothesis tests are widely used for data analysis in sport science. However, the scientific community has been questioning this method and is still looking for alternative approaches for data analyses. In fact, this type of analysis does not allow practical interpretation of the changes observed in athletic performance over time. Therefore, the magnitude-based inference (MBI) method has been increasingly used by researchers and performance analysts. From an applied perspective, this method allows examining the probability of finding meaningful differences in assessed variables. In addition, the MBI enables precise assessment of individual changes, which may be releva nt to sport performance. The aim of this article is to present and discuss the application of the individual MBI analysis. Based on this purpose, the manuscript covers the following topics: 1) utilization of data analysis in real world settings; 2) basic concepts of the MBI; 3) applying the MBI approach in sport science; 4) qualitative classifications based on observed changes; 5) different methods to determine the smallest worthwhile change and the typical error; 6) data analysis and interpretation. We hope that this study will encourage practitioners and r esearchers to implement this novel statistical approach in their daily routines, for analysis and interpretation of data collected during physical performance measurements.(AU)

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In the clinical research process, the formulation of a well-founded hypothesis and objectives concordant with the research question are key to the proper conduct of the project. The following article reviews the fundamental principles for the adequate formulation of hypotheses and objectives of clinical research projects, providing practical recommendations and examples.

En el proceso de investigación clínica, la formulación de una hipótesis bien fundamentada y objetivos concordantes con la pregunta de investigación, son claves para la adecuada conducción del proyecto. El siguiente artículo revisa los principios fundamentales para la formulación adecuada de hipótesis y objetivos de proyectos de investigación clínica, proporcionando recomendaciones prácticas y ejemplos.

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Dando continuidade aos artigos da série "Perguntas que você sempre quis fazer, mas nunca teve coragem", que tem como objetivo responder e sugerir referências para o melhor entendimento das principais dúvidas dos pesquisadores do Hospital de Clínicas de Porto Alegre sobre estatística, este segundo artigo se propõe a responder às principais dúvidas levantadas sobre Teste de Hipóteses. São discutidas questões referentes à metodologia de um teste de hipóteses na concepção clássica de Inferência Estatística, bem como tamanho de efeito, tipos de erros, valor de p e poder. Os conceitos são abordados numa linguagem acessível ao público leigo e diversas referências são sugeridas para os curiosos em relação ao tema. (AU)

Continuing the series of articles "Questions you have always wanted to ask, but never had the courage to", which aims to answer the most common questions of researchers at Hospital de Clínicas de Porto Alegre regarding statistics and to suggest references for a better understanding, this second article addresses the topic of hypothesis testing. The hypothesis testing method is discussed from a classical conception of statistical inference, including effect size, type of errors, p-value and power. The concepts are explained in plain language for lay readers and several references are suggested for those curious about the topic. (AU)

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El cáncer constituye un serio problema de salud a nivel mundial. Las estimaciones, en cuanto a incidencia y mortalidad, no son nada halagüeñas, en especial para los países subdesarrollados. Durante las últimas décadas se han realizado importantes contribuciones a la comprensión de la carcinogénesis humana, sobre todo desde la perspectiva ecológica y evolutiva. Los objetivos del presente trabajo se centran en: destacar las principales hipótesis que desde dicha perspectiva, tratan de explicar la etiología de los tumores malignos, así como adecuar las que, a la luz de los hallazgos recientes o cotejadas con datos empíricos, parecen más factibles. La hipótesis tradicionalmente aceptada se basa en la carcinogénesis en múltiples etapas y explica de manera satisfactoria algunos aspectos del proceso; aunque conlleva a falacias de lógica, como la conclusión que dos tercios de los cánceres humanos obedecen a la mala suerte. Por su parte, la hipótesis de la oncogénesis adaptativa parece adecuarse de manera más realística a las complejas relaciones ecológicas que se establecen entre las células malignas, las células normales y el microambiente celular; capaces de originar fenómenos tan inadmisibles, como la cooperación de células normales en la progresión tumoral o la adopción por parte de las células malignas de estrategias evolutivamente estables. De hecho, la oncogénesis adaptativa incluso puede ser extendida al nivel del macroambiente poblacional y social. Su conclusión definitiva no hace más que reiterar la importancia de la prevención como la medida más eficaz para reducir la carga global de enfermedad por cáncer(AU)

Cancer is a serious health problem worldwide. Estimates, in terms of incidence and mortality, are not at all promising especially for underdeveloped countries. During the last decades, important contributions have been made to the understanding of human carcinogenesis, especially from the ecological and evolutionary perspective. The objectives of this work are focused on: highlighting the main hypotheses that, from this perspective, try to explain the etiology of malignant tumors, as well as adapting those that, in the light of recent findings or collated with empirical data, seem more feasible. The traditionally accepted hypothesis is based on multi-stage carcinogenesis; and satisfactorily explains some aspects of the process; although it leads to logic fallacies, such as the conclusion that two thirds of human cancers obey to bad luck. On the other hand, the hypothesis of adaptive oncogenesis seems to adapt more realistically to the complex ecological relationships established between malignant cells, normal cells, and the cellular microenvironment; capable of originating such inadmissible phenomena, such as the cooperation of normal cells in tumor progression, or the adoption by malignant cells of evolutionarily stable strategies. In fact, adaptive oncogenesis can even be extended to the level of the population and social "macroenvironment". Its final conclusion does nothing but reiterate the importance of prevention as the most effective measure to reduce the global burden of cancer disease(AU)

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