Determining Sample Size and Power in Research Studies

Determining Sample Size and Power in Research Studies

Author: J. P. Verma

Publisher: Springer Nature

Published: 2020-07-20

Total Pages: 138

ISBN-13: 9811552045

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This book addresses sample size and power in the context of research, offering valuable insights for graduate and doctoral students as well as researchers in any discipline where data is generated to investigate research questions. It explains how to enhance the authenticity of research by estimating the sample size and reporting the power of the tests used. Further, it discusses the issue of sample size determination in survey studies as well as in hypothesis testing experiments so that readers can grasp the concept of statistical errors, minimum detectable difference, effect size, one-tail and two-tail tests and the power of the test. The book also highlights the importance of fixing these boundary conditions in enhancing the authenticity of research findings and improving the chances of research papers being accepted by respected journals. Further, it explores the significance of sample size by showing the power achieved in selected doctoral studies. Procedure has been discussed to fix power in the hypothesis testing experiment. One should usually have power at least 0.8 in the study because having power less than this will have the issue of practical significance of findings. If the power in any study is less than 0.5 then it would be better to test the hypothesis by tossing a coin instead of organizing the experiment. It also discusses determining sample size and power using the freeware G*Power software, based on twenty-one examples using different analyses, like t-test, parametric and non-parametric correlations, multivariate regression, logistic regression, independent and repeated measures ANOVA, mixed design, MANOVA and chi-square.


The Health Effects of Cannabis and Cannabinoids

The Health Effects of Cannabis and Cannabinoids

Author: National Academies of Sciences, Engineering, and Medicine

Publisher: National Academies Press

Published: 2017-03-31

Total Pages: 487

ISBN-13: 0309453070

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Significant changes have taken place in the policy landscape surrounding cannabis legalization, production, and use. During the past 20 years, 25 states and the District of Columbia have legalized cannabis and/or cannabidiol (a component of cannabis) for medical conditions or retail sales at the state level and 4 states have legalized both the medical and recreational use of cannabis. These landmark changes in policy have impacted cannabis use patterns and perceived levels of risk. However, despite this changing landscape, evidence regarding the short- and long-term health effects of cannabis use remains elusive. While a myriad of studies have examined cannabis use in all its various forms, often these research conclusions are not appropriately synthesized, translated for, or communicated to policy makers, health care providers, state health officials, or other stakeholders who have been charged with influencing and enacting policies, procedures, and laws related to cannabis use. Unlike other controlled substances such as alcohol or tobacco, no accepted standards for safe use or appropriate dose are available to help guide individuals as they make choices regarding the issues of if, when, where, and how to use cannabis safely and, in regard to therapeutic uses, effectively. Shifting public sentiment, conflicting and impeded scientific research, and legislative battles have fueled the debate about what, if any, harms or benefits can be attributed to the use of cannabis or its derivatives, and this lack of aggregated knowledge has broad public health implications. The Health Effects of Cannabis and Cannabinoids provides a comprehensive review of scientific evidence related to the health effects and potential therapeutic benefits of cannabis. This report provides a research agendaâ€"outlining gaps in current knowledge and opportunities for providing additional insight into these issuesâ€"that summarizes and prioritizes pressing research needs.


Research Methods for Organizational Studies

Research Methods for Organizational Studies

Author: Donald P. Schwab

Publisher: Psychology Press

Published: 2013-06-17

Total Pages: 320

ISBN-13: 1135704910

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This revision of a best selling research methods textbook introduces social science methods as applied broadly to the study of issues that arise as part of organizational life. These include issues involving organizational participants such as managers, teachers, customers, patients and clients, and transactions within and between organizations. In this new edition, chapter 19 now focuses on describing the modeling process and outcomes. An entirely new chapter 20 now addresses challenges to modeling. It goes substantially beyond a discussion of statistical inference. It also discusses issues in interpreting variance, explained estimates, and standardized and unstandardized regression coefficients. A new capstone chapter 21 helps students recognize good research. This textbook is accompanied by an Instructor's Manual for course use.


Women and Health Research

Women and Health Research

Author: Institute of Medicine

Publisher: National Academies Press

Published: 1994-02-01

Total Pages: 286

ISBN-13: 030904992X

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In the nineteenth century some scientists argued that women should not be educated because thinking would use energy needed by the uterus for reproduction. The proof? Educated women had a lower birth rate. Today's researchers can only shake their heads at such reasoning. Yet professional journals and the popular press are increasingly criticizing medical research for ignoring women's health issues. Women and Health Research examines the facts behind the public's perceptions about women participating as subjects in medical research. With the goal of increasing researchers' awareness of this important topic, the book explores issues related to maintaining justice (in its ethical sense) in clinical studies. Leading experts present general principles for the ethical conduct of research on womenâ€"principles that are especially important in the light of recent changes in federal policy on the inclusion of women in clinical research. Women and Health Research documents the historical shift from a paternalistic approach by researchers toward women and a disproportionate reliance on certain groups for research to one that emphasizes proper access for women as subjects in clinical studies in order to ensure that women receive the benefits of research. The book addresses present-day challenges to equity in four areas: Scientificâ€"Do practical aspects of scientific research work at cross-purposes to gender equity? Focusing on drug trials, the authors identify rationales for excluding people from research based on demographics. Social and Ethicalâ€"The authors offer compelling discussions on subjectivity in science, the evidence for male bias, and issues related to race and ethnicity, as well as the recruitment, retention, and protection of research participants. Legalâ€"Women and Health Research reviews federal research policies that affect the inclusion of women and evaluates the basis for researchers' fears about liability, citing court cases. Riskâ€"The authors focus on risks to reproduction and offspring in clinical drug trials, exploring how risks can be identified for study participants, who should make the assessment of risk and benefit for participation in a clinical study, and how legal implications could be addressed. This landmark study will be of immediate use to the research community, policymakers, women's health advocates, attorneys, and individuals.


Finding What Works in Health Care

Finding What Works in Health Care

Author: Institute of Medicine

Publisher: National Academies Press

Published: 2011-07-20

Total Pages: 267

ISBN-13: 0309164257

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Healthcare decision makers in search of reliable information that compares health interventions increasingly turn to systematic reviews for the best summary of the evidence. Systematic reviews identify, select, assess, and synthesize the findings of similar but separate studies, and can help clarify what is known and not known about the potential benefits and harms of drugs, devices, and other healthcare services. Systematic reviews can be helpful for clinicians who want to integrate research findings into their daily practices, for patients to make well-informed choices about their own care, for professional medical societies and other organizations that develop clinical practice guidelines. Too often systematic reviews are of uncertain or poor quality. There are no universally accepted standards for developing systematic reviews leading to variability in how conflicts of interest and biases are handled, how evidence is appraised, and the overall scientific rigor of the process. In Finding What Works in Health Care the Institute of Medicine (IOM) recommends 21 standards for developing high-quality systematic reviews of comparative effectiveness research. The standards address the entire systematic review process from the initial steps of formulating the topic and building the review team to producing a detailed final report that synthesizes what the evidence shows and where knowledge gaps remain. Finding What Works in Health Care also proposes a framework for improving the quality of the science underpinning systematic reviews. This book will serve as a vital resource for both sponsors and producers of systematic reviews of comparative effectiveness research.


Handbook of EHealth Evaluation

Handbook of EHealth Evaluation

Author: Francis Yin Yee Lau

Publisher:

Published: 2016-11

Total Pages: 487

ISBN-13: 9781550586015

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To order please visit https://onlineacademiccommunity.uvic.ca/press/books/ordering/


Studying A Study and Testing a Test

Studying A Study and Testing a Test

Author: Richard K. Riegelman

Publisher: Lippincott Williams & Wilkins

Published: 2012-06-18

Total Pages: 353

ISBN-13: 0781774268

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Rev. ed. of: Studying a study and testing a test / Richard K. Riegelman.


Handbook of Research Methods for Studying Daily Life

Handbook of Research Methods for Studying Daily Life

Author: Matthias R. Mehl

Publisher: Guilford Publications

Published: 2013-10-01

Total Pages: 705

ISBN-13: 1462513050

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Bringing together leading authorities, this unique handbook reviews the breadth of current approaches for studying how people think, feel, and behave in everyday environments, rather than in the laboratory. The volume thoroughly describes experience sampling methods, diary methods, physiological measures, and other self-report and non-self-report tools that allow for repeated, real-time measurement in natural settings. Practical guidance is provided to help the reader design a high-quality study, select and implement appropriate methods, and analyze the resulting data using cutting-edge statistical techniques. Applications across a wide range of psychological subfields and research areas are discussed in detail.


The Design of Studies for Medical Research

The Design of Studies for Medical Research

Author: David Machin

Publisher: John Wiley & Sons

Published: 2005-05-13

Total Pages: 286

ISBN-13: 0470012986

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The same careful rigour imposed on the design of phase III randomised controlled trials is not always applied to medical research in other areas such as trials conducted at earlier stages of drug development. With the emphasis that is now placed on evidence-based medicine, such care and rigour will inevitably impact on these areas with increasing attention turned to the quality of design. This title describes what principles can be used to structure research effectively allowing for the required degree of accuracy. Written by two best selling authors, this book includes many examples from medical literature and will be of great value to all groups conducting studies at the interface of clinical and laboratory research.


Essentials of Writing Biomedical Research Papers. Second Edition

Essentials of Writing Biomedical Research Papers. Second Edition

Author: Mimi Zeiger

Publisher: McGraw Hill Professional

Published: 1999-10-21

Total Pages: 464

ISBN-13: 0071503854

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Provides immediate help for anyone preparing a biomedical paper by givin specific advice on organizing the components of the paper, effective writing techniques, writing an effective results sections, documentation issues, sentence structure and much more. The new edition includes new examples from the current literature including many involving molecular biology, expanded exercises at the end of the book, revised explanations on linking key terms, transition clauses, uses of subheads, and emphases. If you plan to do any medical writing, read this book first and get an immediate advantage.