This document discusses statistical tests for analyzing categorical data. It begins by defining categorical variables and the prerequisites for selecting a statistical test. It then outlines various bivariate and multivariate tests that can be used for unpaired and paired categorical data, including chi-square tests, Fisher's exact test, McNemar's test, and logistic regression. It also discusses measures of association like odds ratios. Examples are provided to illustrate McNemar's test and calculating interrater reliability using Cohen's kappa. The document concludes by emphasizing the importance of selecting the appropriate statistical method based on one's data and checking assumptions.
Explains how to select a statistical test suitable for your hypothesis. Suggests points to consider before deciding about a test. Gives a list of commonly used parametric and non-parametric tests with their purposes of use.
Explains how to select a statistical test suitable for your hypothesis. Suggests points to consider before deciding about a test. Gives a list of commonly used parametric and non-parametric tests with their purposes of use.
Clinical Validation of Copy Number Variants Using the AMP GuidelinesGolden Helix
The common approaches to detecting copy number variants (CNVs) are chromosomal microarray and MLPA. However, both options increase analysis time, per sample costs, and are limited to the size of CNV events that can be detected. VarSeq’s CNV caller, on the other hand, allows users to detect CNVs from the coverage profile stored in the BAM file, which allows you to utilize your existing NGS data and perform the analysis all in one suite. Coupled with this innovative feature is the ability to annotate CNV events against a variety of databases, and by incorporating our VSClinical AMP workflow, we can now assess CNVs as potential biomarkers. Most importantly, Golden Helix CancerKB is an AMP workflow feature that provides expert-curated biomarker interpretations, including those for common somatic CNVs, that will streamline the analysis time and report generation.
In this demonstration we will cover:
Setting up the VS-CNV caller using BAM files from whole exome data
Filtering down to high quality, high confidence CNV events
Annotating CNVs using publicly curated catalogs and databases
Adding clinically relevant CNVs to the VSClinical AMP workflow
Utilizing Golden Helix CancerKB to obtain expert-curated interpretations
Showing updated features and polishes to the software
Together, VarSeq incorporates the ability to accurately call and annotate CNVs and evaluate germline and somatic mutations according to the ACMG and AMP guidelines, respectively. This webcast demonstration will provide insight into these best practice workflows and will hopefully show you how you can implement this top-quality software into your pipeline solution.
Dr. Kelvin Chan gave a short explanation on what real-world evidence (RWE) is, how they can be used in cancer care and what benefits patients can get from the real-world evidence. He will also introduce the Canadian Real-world Evidence for Value of Cancer Drugs (CanREValue) collaboration, which is a pan-Canadian collaboration working on developing a framework to generate and use real-world evidence to inform cancer drug funding decisions.
The webinar was followed by an interactive question & answer session.
Big data vs the RCT - Derek Angus - SSAI2017scanFOAM
A talk by Derek Angus at the 2017 meeting of the Scandinavian Society of Anaestesiology and Intensive Care Medicine.
All of the conference content can be found here: https://scanfoam.org/ssai2017/
Developed in collaboration between scanFOAM, SSAI and SFAI.
Enhance Genomic Research with Polygenic Risk Score Calculations in SVSGolden Helix
Golden Helix’s SNP & Variation Suite (SVS) has been used by researchers around the world to do trait analysis and association testing on large cohorts of samples in both humans and other species. The latest SVS release introduces a significant leap in capabilities, with a focus on advanced Polygenic Risk Score (PRS) calculations. PRS has become a fundamental tool in genomic research, enabling the identification of correlations between genotypic variants and phenotypes across large populations.
This enhancement is particularly relevant for researchers working on large cohorts and meta-analysis. Please join us as we explore:
-SVS Workflow Review: A review of the extensive capabilities of SVS to meaningful insights from large cohorts and association test result datasets
-Computing Polygenic Risk Scores: An overview of the PRS capabilities in SVS, including Clumping and Thresholding and creation of multiple PRS models
-Evaluating and Applying PRS: Evaluating PRS models in-sample and out-of-sample and applying PRS models to perform trait prediction
-Future Implications: Brief exploration of how these advancements in SVS could influence future genomic research.
This webcast will explore how SVS facilitates the creation of multiple PRS models from large-scale genomic data, such as those obtained from extensive cohort studies or comprehensive meta-analyses. Join us to discover how these latest updates in SVS are supporting large-scale genomic research.
Comparison of RECIST 1.0 and 1.1 - Impact on Data ManagementKevin Shea
A review of the two RECIST versions, noting similarities and differences, highlighting the improvements in v.1.1. This information is used to discuss how some of the challenges RECIST presents to data management can be addressed.
ACMG-Based Variant Classification with VSClinicalGolden Helix
Evaluating variants according to the ACMG guidelines can be an extensive process as it requires an in-depth understanding of all available criteria for any variant. Even the most adept clinicians familiar to the guidelines suffer from this tedious manual process and from the challenge of teaching these fundamentals to new technicians. VSClinical is an automated solution to the complex ACMG guidelines process. In this webcast, we will present how VSClinical follows the true-to-form ACMG classification rules. Additionally, users will discover the value of automating the ACMG guidelines to make variant classification consistent and simplify the interpretation process for those less familiar with ACMG criteria.
Similar to Statistical tests for categorical data (20)
New Directions in Targeted Therapeutic Approaches for Older Adults With Mantl...i3 Health
i3 Health is pleased to make the speaker slides from this activity available for use as a non-accredited self-study or teaching resource.
This slide deck presented by Dr. Kami Maddocks, Professor-Clinical in the Division of Hematology and
Associate Division Director for Ambulatory Operations
The Ohio State University Comprehensive Cancer Center, will provide insight into new directions in targeted therapeutic approaches for older adults with mantle cell lymphoma.
STATEMENT OF NEED
Mantle cell lymphoma (MCL) is a rare, aggressive B-cell non-Hodgkin lymphoma (NHL) accounting for 5% to 7% of all lymphomas. Its prognosis ranges from indolent disease that does not require treatment for years to very aggressive disease, which is associated with poor survival (Silkenstedt et al, 2021). Typically, MCL is diagnosed at advanced stage and in older patients who cannot tolerate intensive therapy (NCCN, 2022). Although recent advances have slightly increased remission rates, recurrence and relapse remain very common, leading to a median overall survival between 3 and 6 years (LLS, 2021). Though there are several effective options, progress is still needed towards establishing an accepted frontline approach for MCL (Castellino et al, 2022). Treatment selection and management of MCL are complicated by the heterogeneity of prognosis, advanced age and comorbidities of patients, and lack of an established standard approach for treatment, making it vital that clinicians be familiar with the latest research and advances in this area. In this activity chaired by Michael Wang, MD, Professor in the Department of Lymphoma & Myeloma at MD Anderson Cancer Center, expert faculty will discuss prognostic factors informing treatment, the promising results of recent trials in new therapeutic approaches, and the implications of treatment resistance in therapeutic selection for MCL.
Target Audience
Hematology/oncology fellows, attending faculty, and other health care professionals involved in the treatment of patients with mantle cell lymphoma (MCL).
Learning Objectives
1.) Identify clinical and biological prognostic factors that can guide treatment decision making for older adults with MCL
2.) Evaluate emerging data on targeted therapeutic approaches for treatment-naive and relapsed/refractory MCL and their applicability to older adults
3.) Assess mechanisms of resistance to targeted therapies for MCL and their implications for treatment selection
Basavarajeeyam is an important text for ayurvedic physician belonging to andhra pradehs. It is a popular compendium in various parts of our country as well as in andhra pradesh. The content of the text was presented in sanskrit and telugu language (Bilingual). One of the most famous book in ayurvedic pharmaceutics and therapeutics. This book contains 25 chapters called as prakaranas. Many rasaoushadis were explained, pioneer of dhatu druti, nadi pareeksha, mutra pareeksha etc. Belongs to the period of 15-16 century. New diseases like upadamsha, phiranga rogas are explained.
- Video recording of this lecture in English language: https://youtu.be/lK81BzxMqdo
- Video recording of this lecture in Arabic language: https://youtu.be/Ve4P0COk9OI
- Link to download the book free: https://nephrotube.blogspot.com/p/nephrotube-nephrology-books.html
- Link to NephroTube website: www.NephroTube.com
- Link to NephroTube social media accounts: https://nephrotube.blogspot.com/p/join-nephrotube-on-social-media.html
MANAGEMENT OF ATRIOVENTRICULAR CONDUCTION BLOCK.pdfJim Jacob Roy
Cardiac conduction defects can occur due to various causes.
Atrioventricular conduction blocks ( AV blocks ) are classified into 3 types.
This document describes the acute management of AV block.
Recomendações da OMS sobre cuidados maternos e neonatais para uma experiência pós-natal positiva.
Em consonância com os ODS – Objetivos do Desenvolvimento Sustentável e a Estratégia Global para a Saúde das Mulheres, Crianças e Adolescentes, e aplicando uma abordagem baseada nos direitos humanos, os esforços de cuidados pós-natais devem expandir-se para além da cobertura e da simples sobrevivência, de modo a incluir cuidados de qualidade.
Estas diretrizes visam melhorar a qualidade dos cuidados pós-natais essenciais e de rotina prestados às mulheres e aos recém-nascidos, com o objetivo final de melhorar a saúde e o bem-estar materno e neonatal.
Uma “experiência pós-natal positiva” é um resultado importante para todas as mulheres que dão à luz e para os seus recém-nascidos, estabelecendo as bases para a melhoria da saúde e do bem-estar a curto e longo prazo. Uma experiência pós-natal positiva é definida como aquela em que as mulheres, pessoas que gestam, os recém-nascidos, os casais, os pais, os cuidadores e as famílias recebem informação consistente, garantia e apoio de profissionais de saúde motivados; e onde um sistema de saúde flexível e com recursos reconheça as necessidades das mulheres e dos bebês e respeite o seu contexto cultural.
Estas diretrizes consolidadas apresentam algumas recomendações novas e já bem fundamentadas sobre cuidados pós-natais de rotina para mulheres e neonatos que recebem cuidados no pós-parto em unidades de saúde ou na comunidade, independentemente dos recursos disponíveis.
É fornecido um conjunto abrangente de recomendações para cuidados durante o período puerperal, com ênfase nos cuidados essenciais que todas as mulheres e recém-nascidos devem receber, e com a devida atenção à qualidade dos cuidados; isto é, a entrega e a experiência do cuidado recebido. Estas diretrizes atualizam e ampliam as recomendações da OMS de 2014 sobre cuidados pós-natais da mãe e do recém-nascido e complementam as atuais diretrizes da OMS sobre a gestão de complicações pós-natais.
O estabelecimento da amamentação e o manejo das principais intercorrências é contemplada.
Recomendamos muito.
Vamos discutir essas recomendações no nosso curso de pós-graduação em Aleitamento no Instituto Ciclos.
Esta publicação só está disponível em inglês até o momento.
Prof. Marcus Renato de Carvalho
www.agostodourado.com
Flu Vaccine Alert in Bangalore Karnatakaaddon Scans
As flu season approaches, health officials in Bangalore, Karnataka, are urging residents to get their flu vaccinations. The seasonal flu, while common, can lead to severe health complications, particularly for vulnerable populations such as young children, the elderly, and those with underlying health conditions.
Dr. Vidisha Kumari, a leading epidemiologist in Bangalore, emphasizes the importance of getting vaccinated. "The flu vaccine is our best defense against the influenza virus. It not only protects individuals but also helps prevent the spread of the virus in our communities," he says.
This year, the flu season is expected to coincide with a potential increase in other respiratory illnesses. The Karnataka Health Department has launched an awareness campaign highlighting the significance of flu vaccinations. They have set up multiple vaccination centers across Bangalore, making it convenient for residents to receive their shots.
To encourage widespread vaccination, the government is also collaborating with local schools, workplaces, and community centers to facilitate vaccination drives. Special attention is being given to ensuring that the vaccine is accessible to all, including marginalized communities who may have limited access to healthcare.
Residents are reminded that the flu vaccine is safe and effective. Common side effects are mild and may include soreness at the injection site, mild fever, or muscle aches. These side effects are generally short-lived and far less severe than the flu itself.
Healthcare providers are also stressing the importance of continuing COVID-19 precautions. Wearing masks, practicing good hand hygiene, and maintaining social distancing are still crucial, especially in crowded places.
Protect yourself and your loved ones by getting vaccinated. Together, we can help keep Bangalore healthy and safe this flu season. For more information on vaccination centers and schedules, residents can visit the Karnataka Health Department’s official website or follow their social media pages.
Stay informed, stay safe, and get your flu shot today!
Tom Selleck Health: A Comprehensive Look at the Iconic Actor’s Wellness Journeygreendigital
Tom Selleck, an enduring figure in Hollywood. has captivated audiences for decades with his rugged charm, iconic moustache. and memorable roles in television and film. From his breakout role as Thomas Magnum in Magnum P.I. to his current portrayal of Frank Reagan in Blue Bloods. Selleck's career has spanned over 50 years. But beyond his professional achievements. fans have often been curious about Tom Selleck Health. especially as he has aged in the public eye.
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Introduction
Many have been interested in Tom Selleck health. not only because of his enduring presence on screen but also because of the challenges. and lifestyle choices he has faced and made over the years. This article delves into the various aspects of Tom Selleck health. exploring his fitness regimen, diet, mental health. and the challenges he has encountered as he ages. We'll look at how he maintains his well-being. the health issues he has faced, and his approach to ageing .
Early Life and Career
Childhood and Athletic Beginnings
Tom Selleck was born on January 29, 1945, in Detroit, Michigan, and grew up in Sherman Oaks, California. From an early age, he was involved in sports, particularly basketball. which played a significant role in his physical development. His athletic pursuits continued into college. where he attended the University of Southern California (USC) on a basketball scholarship. This early involvement in sports laid a strong foundation for his physical health and disciplined lifestyle.
Transition to Acting
Selleck's transition from an athlete to an actor came with its physical demands. His first significant role in "Magnum P.I." required him to perform various stunts and maintain a fit appearance. This role, which he played from 1980 to 1988. necessitated a rigorous fitness routine to meet the show's demands. setting the stage for his long-term commitment to health and wellness.
Fitness Regimen
Workout Routine
Tom Selleck health and fitness regimen has evolved. adapting to his changing roles and age. During his "Magnum, P.I." days. Selleck's workouts were intense and focused on building and maintaining muscle mass. His routine included weightlifting, cardiovascular exercises. and specific training for the stunts he performed on the show.
Selleck adjusted his fitness routine as he aged to suit his body's needs. Today, his workouts focus on maintaining flexibility, strength, and cardiovascular health. He incorporates low-impact exercises such as swimming, walking, and light weightlifting. This balanced approach helps him stay fit without putting undue strain on his joints and muscles.
Importance of Flexibility and Mobility
In recent years, Selleck has emphasized the importance of flexibility and mobility in his fitness regimen. Understanding the natural decline in muscle mass and joint flexibility with age. he includes stretching and yoga in his routine. These practices help prevent injuries, improve posture, and maintain mobilit
New Drug Discovery and Development .....NEHA GUPTA
The "New Drug Discovery and Development" process involves the identification, design, testing, and manufacturing of novel pharmaceutical compounds with the aim of introducing new and improved treatments for various medical conditions. This comprehensive endeavor encompasses various stages, including target identification, preclinical studies, clinical trials, regulatory approval, and post-market surveillance. It involves multidisciplinary collaboration among scientists, researchers, clinicians, regulatory experts, and pharmaceutical companies to bring innovative therapies to market and address unmet medical needs.
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Ve...kevinkariuki227
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Verified Chapters 1 - 19, Complete Newest Version.pdf
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Verified Chapters 1 - 19, Complete Newest Version.pdf
Lung Cancer: Artificial Intelligence, Synergetics, Complex System Analysis, S...Oleg Kshivets
RESULTS: Overall life span (LS) was 2252.1±1742.5 days and cumulative 5-year survival (5YS) reached 73.2%, 10 years – 64.8%, 20 years – 42.5%. 513 LCP lived more than 5 years (LS=3124.6±1525.6 days), 148 LCP – more than 10 years (LS=5054.4±1504.1 days).199 LCP died because of LC (LS=562.7±374.5 days). 5YS of LCP after bi/lobectomies was significantly superior in comparison with LCP after pneumonectomies (78.1% vs.63.7%, P=0.00001 by log-rank test). AT significantly improved 5YS (66.3% vs. 34.8%) (P=0.00000 by log-rank test) only for LCP with N1-2. Cox modeling displayed that 5YS of LCP significantly depended on: phase transition (PT) early-invasive LC in terms of synergetics, PT N0—N12, cell ratio factors (ratio between cancer cells- CC and blood cells subpopulations), G1-3, histology, glucose, AT, blood cell circuit, prothrombin index, heparin tolerance, recalcification time (P=0.000-0.038). Neural networks, genetic algorithm selection and bootstrap simulation revealed relationships between 5YS and PT early-invasive LC (rank=1), PT N0—N12 (rank=2), thrombocytes/CC (3), erythrocytes/CC (4), eosinophils/CC (5), healthy cells/CC (6), lymphocytes/CC (7), segmented neutrophils/CC (8), stick neutrophils/CC (9), monocytes/CC (10); leucocytes/CC (11). Correct prediction of 5YS was 100% by neural networks computing (area under ROC curve=1.0; error=0.0).
CONCLUSIONS: 5YS of LCP after radical procedures significantly depended on: 1) PT early-invasive cancer; 2) PT N0--N12; 3) cell ratio factors; 4) blood cell circuit; 5) biochemical factors; 6) hemostasis system; 7) AT; 8) LC characteristics; 9) LC cell dynamics; 10) surgery type: lobectomy/pneumonectomy; 11) anthropometric data. Optimal diagnosis and treatment strategies for LC are: 1) screening and early detection of LC; 2) availability of experienced thoracic surgeons because of complexity of radical procedures; 3) aggressive en block surgery and adequate lymph node dissection for completeness; 4) precise prediction; 5) adjuvant chemoimmunoradiotherapy for LCP with unfavorable prognosis.
Ozempic: Preoperative Management of Patients on GLP-1 Receptor Agonists Saeid Safari
Preoperative Management of Patients on GLP-1 Receptor Agonists like Ozempic and Semiglutide
ASA GUIDELINE
NYSORA Guideline
2 Case Reports of Gastric Ultrasound
NVBDCP.pptx Nation vector borne disease control programSapna Thakur
NVBDCP was launched in 2003-2004 . Vector-Borne Disease: Disease that results from an infection transmitted to humans and other animals by blood-feeding arthropods, such as mosquitoes, ticks, and fleas. Examples of vector-borne diseases include Dengue fever, West Nile Virus, Lyme disease, and malaria.
Report Back from SGO 2024: What’s the Latest in Cervical Cancer?bkling
Are you curious about what’s new in cervical cancer research or unsure what the findings mean? Join Dr. Emily Ko, a gynecologic oncologist at Penn Medicine, to learn about the latest updates from the Society of Gynecologic Oncology (SGO) 2024 Annual Meeting on Women’s Cancer. Dr. Ko will discuss what the research presented at the conference means for you and answer your questions about the new developments.
Report Back from SGO 2024: What’s the Latest in Cervical Cancer?
Statistical tests for categorical data
1. Statistical tests for categorical data
Dr. S. A. Rizwan, M.D.
Public Health Specialist
SBCM, Joint Program – Riyadh
Ministry of Health, Kingdom of Saudi Arabia
2. Learning objectives
Demystifying statistics! SBCM, Joint Program – RiyadhSBCM, Joint Program – Riyadh
• Examine the relationship between categorical
variables
• Construct a contingency table for two categorical
variables
• Describe the approach to statistical testing of
categorical variables
3. Revise: Categorical variables
Demystifying statistics! SBCM, Joint Program – RiyadhSBCM, Joint Program – Riyadh
• Categorical (qualitative)
• Nominal (no order)
• Dichotomous, binary, binomial
• Polychotomous
• Ordinal (ordered)
• Answers “what?”
• Qualitative data is categorised
5. Revise: Prerequisites for a test
Demystifying statistics! SBCM, Joint Program – RiyadhSBCM, Joint Program – Riyadh
• How many variables are there?
• What is the nature of dependent and
independent variable?
• How many categories are there in the
categorical variable?
• Does the continuous variable follow normal
distribution?
• Is there any pairing in the data/variables?
7. Statistical tests: Bivariate
SBCM, Joint Program – RiyadhSBCM, Joint Program – RiyadhDemystifying statistics!
For unpaired data For paired data
• If assumptions for Chi square are met
• Chi-square (>= 2 levels)
• If assumptions for Chi square NOT met
• Fisher’s exact (>= 2 levels)
• If the groups are paired
• McNemar (if 2 levels)
• RM logistic regression (if >2 levels)
• Interrater reliability analysis
8. Statistical tests: Multivariate
SBCM, Joint Program – RiyadhSBCM, Joint Program – Riyadh
For unpaired data For matched data
Demystifying statistics!
• If DV is binary and >1 IV
• Binary logistic regression
• If DV is polychotomousand >1 IV
• Multinomial logistic regression
• If DV is ordinal and >1 IV
• Ordinal regression
• If the groups are matched
• Conditional logistic regression
• If repeated measurements
• RM logistic regression
10. Statistical tests: Special
SBCM, Joint Program – RiyadhSBCM, Joint Program – RiyadhDemystifying statistics!
For ordered categorical variable
• Chi square test for trend
Passed Failed Total
R1 100 78 178
R2 175 173 348
R3 42 59 101
Total 317 310 627
12. Contingency table
SBCM, Joint Program – RiyadhSBCM, Joint Program – RiyadhDemystifying statistics!
• Used in bivariate situations
• Use counts, not percentages
• No one-sided tests
• Each subject counted only once
• Explain significant findings
13. Some selected topics
SBCM, Joint Program – RiyadhSBCM, Joint Program – RiyadhDemystifying statistics!
• Covered in other classes
• Chi square test
• Cochran-Mantel-Haenszel test
• Regression
• In this class we will cover basics of:
• Fisher’s exact test
• McNemar test
• Interrater reliability analysis (Agreement statistics)
14. Thought exercise 1
SBCM, Joint Program – RiyadhSBCM, Joint Program – RiyadhDemystifying statistics!
• In a study a researcher tested a perfume on 9 rats and used water as
the control on 9 other rats. Among the perfume group 1 rat showed
restlessness whereas among the control group 4 rats showed
restlessness. Determine if there is an association between perfume
and restlessness.
15. Thought exercise 2
SBCM, Joint Program – RiyadhSBCM, Joint Program – RiyadhDemystifying statistics!
• 22 pairs of twins were enrolled in the study. One of the twins
smoked, the other didn’t. The twins were followed to see which twin
died first. For 17 pairs of twins, the smoking twin died first and for 5
pairs of twins, the non-smoking twin died first.
16. Thought exercise 3
SBCM, Joint Program – RiyadhSBCM, Joint Program – RiyadhDemystifying statistics!
• All 100 pathological slides were observed by 2 pathologists. The
were supposed to classify the disease as mild, moderate and severe.
Pathologist 1 classified 60, 30, 10 and pathologist 2 classified 50, 30,
20 as mild, moderate and severe. Both pathologists agreed that 44
were mild, 20 were moderate and 6 were severe and disagreed on
the remaining slides. Calculate the agreement between the two
pathologists.
17. Fisher’s exact test
SBCM, Joint Program – RiyadhSBCM, Joint Program – RiyadhDemystifying statistics!
• Used in the place of chi square
test for independence when the
cell counts are sparse
• More than 20% of the cells have
expected frequencies of <5
19. Fisher’s exact test
SBCM, Joint Program – RiyadhSBCM, Joint Program – RiyadhDemystifying statistics!
• 6 possible tables for the observed
marginal totals: 9, 9, 5, 13.
• p-value is calculated by summing
all probabilities less than or equal
to the probability of the observed
table
20. Fisher’s exact test
SBCM, Joint Program – RiyadhSBCM, Joint Program – RiyadhDemystifying statistics!
• The observed table (Table II) has
probability = 0.132
• P-value for the Fisher’s exact test =
Pr (Table II) + Pr (Table V) + Pr
(Table I) + Pr (Table VI)
• = 0.132 + 0.132 + 0.0147 + 0.0147
= 0.293
21. McNemar test
SBCM, Joint Program – RiyadhSBCM, Joint Program – RiyadhDemystifying statistics!
• When data are paired and the outcome of interest is a proportion,
the McNemar Test is used
• Pair-Matched data can come from
• Case-control studies where each case has a matching control
(matched on age, gender, race, etc.)
• Twins studies – the matched pairs are twins
• Before - After data
• Outcome is presence (+) or absence (-) of some characteristic
measured on the same individual at two time points
22. McNemar test: matched case-control
SBCM, Joint Program – RiyadhSBCM, Joint Program – RiyadhDemystifying statistics!
• a - number of case-control pairs where both are exposed
• b - number of case-control pairs where the case is exposed and the
control is unexposed
• c - number of case-control pairs where the case is
• unexposed and the control is exposed
• d - number of case-control pairs where both are unexposed
• The counts in the table for a case-control study are numbers of pairs
not numbers of individuals.
23. McNemar test: before-after study
SBCM, Joint Program – RiyadhSBCM, Joint Program – RiyadhDemystifying statistics!
• a - number of subjects with characteristic present both
before and after treatment
• b - number of subjects where characteristic is present
before but not after
• c - number of subjects where characteristic is present
after but not before
• d - number of subjects with the characteristic absent
both before and after treatment.
24. McNemar test
SBCM, Joint Program – RiyadhSBCM, Joint Program – RiyadhDemystifying statistics!
• Calculated using the counts in the ‘b’ and
‘c’ cells of the table
• The sampling distribution Chi-square
distribution, the degrees of freedom = 1
• For a test with alpha = 0.05, the critical
value for the McNemar statistic = 3.84.
26. McNemar test
SBCM, Joint Program – RiyadhSBCM, Joint Program – RiyadhDemystifying statistics!
• Critical value for Chi-square
distribution with 1 df = 3.84, p
value = 0.01
• Conclusion: A significantly different
proportion of smoking twins died
first compared to their non-
smoking twin indicating a different
risk of death associated with
smoking (p = 0.01)
27. Agreement statistics
SBCM, Joint Program – RiyadhSBCM, Joint Program – RiyadhDemystifying statistics!
• Many types of agreement statistics depending on
• Data type
• Type of repetition
• Internal consistency
28. Agreement statistics
SBCM, Joint Program – RiyadhSBCM, Joint Program – RiyadhDemystifying statistics!
• Cohen’s kappa
• Measures the agreement between
two raters who each classify N
items into C mutually exclusive
categories
• Used when responses are
categorical
31. Advanced learning
Demystifying statistics! SBCM, Joint Program – RiyadhSBCM, Joint Program – Riyadh
• Chi square test for trend
• Special cases of logistic regression
• Repeated measures logistic regression
• Weighted kappa
• Other measures of agreement analysis
32. Take home messages
Demystifying statistics! SBCM, Joint Program – RiyadhSBCM, Joint Program – Riyadh
• Many approaches are available for analysing categorical data
• Choose a method appropriate for your problem
• Check that the assumptions of the method are valid
• Make conclusions based on the results of the test