scholarly journals Twinning Rates in Isolates

2016 ◽  
Vol 19 (6) ◽  
pp. 673-678 ◽  
Author(s):  
Johan Fellman
Keyword(s):  
General Population ◽  
Confidence Intervals ◽  
Statistical Methods ◽  
Extreme Values ◽  
Statistical Analyses ◽  
Isolated Populations ◽  
Southwestern Part ◽  
Variance Formula ◽  
Random Fluctuations ◽  
Mountain Villages

The aim of this study was to investigate the twinning rates (TWRs) in isolates relative to the TWRs in the surrounding populations. It is not uncommon that the TWR shows extreme values (high or low rates) within isolated subpopulations. Starting from the isolated populations of the Åland Islands in Finland (high rates), we enlarged our studies to other isolated subpopulations in other countries: the island of Gotland (high rates), the county of Älvsborg located in the southwestern part of Sweden (low rates), and mountain villages in Norway. In our statistical analyses, we paid special attention to the robustness of the variance formula of the TWR and to alternative confidence intervals for the TWR. Particularly, we show how to obtain the most precise confidence intervals for the twinning rates. These statistical methods are crucial when the extreme TWRs within subpopulations are compared with the TWRs within the general population. One must decide whether the differences are real or caused by random fluctuations within the small isolates.

scholarly journals Editorial, special issue on “Advances in Robust Statistics”

METRON ◽  
2021 ◽  
Author(s):  
Marco Riani ◽  
Mia Hubert
Keyword(s):  
Statistical Methods ◽  
Robust Statistics ◽  
Statistical Analyses ◽  
Striking Feature ◽  
Special Issue ◽  
Current State ◽  
Editorial Special Issue ◽  
Data Points ◽  
Robust Statistical Methods

AbstractStarting with 2020 volume, the journal Metron has decided to celebrate the centenary since its foundation with three special issues. This volume is dedicated to robust statistics. A striking feature of most applied statistical analyses is the use of methods that are well known to be sensitive to outliers or to other departures from the postulated model. Robust statistical methods provide useful tools for reducing this sensitivity, through the detection of the outliers by first fitting the majority of the data and then by flagging deviant data points. The six papers in this issue cover a wide orientation in all fields of robustness. This editorial first provides some facts about the history and current state of robust statistics and then summarizes the contents of each paper.

EXPRESS: A meta-analysis of aspirin and subarachnoid haemorrhage in patients with intracranial aneurysms yields different results to the general population

2021 ◽  
pp. 174749302110048
Author(s):  
Frederick Ewbank ◽  
Jacqueline Birks ◽  
Diederik Bulters
Keyword(s):  
General Population ◽  
Subarachnoid Haemorrhage ◽  
Confidence Intervals ◽  
Random Effects ◽  
Intracranial Aneurysms ◽  
Meta Analysis ◽  
Risk Of Bias ◽  
Random Effects Models ◽  
Hazard Ratios ◽  
Unruptured Intracranial Aneurysms

Abstract Background Some studies have shown a protective association between aspirin use and subarachnoid haemorrhage (SAH). Other studies have found no relationship or the reverse. These studies differ in their study populations and definitions of SAH. Aims Our aim was to establish 1) if there is an association between aspirin and SAH, 2) how this differs between the general population and those with intracranial aneurysms. Summary of review Studies reporting aspirin use and the occurrence of SAH were included and grouped based on population (general population vs aneurysm population). Odds ratios, hazard ratios and confidence intervals were combined in random-effects models. 11 studies were included. Overall, there was an association between aspirin and SAH (OR 0.68 [0.48, 0.96]). However, populations were diverse and heterogeneity between studies high (p<0.00001), questioning the validity of combining these studies and justifying analysis by population. In the general population there was no difference in aspirin use between individuals with and without SAH (OR 1.15 [0.96, 1.38]). In patients with intracranial aneurysms, aspirin use was greater in patients without SAH (OR 0.37 [0.24, 0.58]), although these studies were at higher risk of bias. Conclusions There is an association between aspirin use and SAH in patients with intracranial aneurysms. This apparent protective relationship is not seen in the general population. Prospective randomised studies are required to further investigate the effect of aspirin on unruptured intracranial aneurysms.

Galectin-3 is inversely associated with cardiorespiratory fitness in the general population

2021 ◽  
Vol 28 (Supplement_1) ◽  
Author(s):  
M Haid ◽  
M Bahls ◽  
M Doerr ◽  
S Felix ◽  
S Zylla ◽  
...  
Keyword(s):  
General Population ◽  
Oxygen Uptake ◽  
Cardiorespiratory Fitness ◽  
Extreme Values ◽  
Cardiopulmonary Exercise Testing ◽  
Left Ventricular ◽  
Left Ventricular Ejection ◽  
Linear Regression Models ◽  
Ventricular Ejection Fraction ◽  
Galectin 3

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Low cardiorespiratory fitness (CRF) is associated with high mortality and morbidity. Galectin-3 (Gal-3) is a prognostic biomarker for fibrosis, different cancers, renal impairment and, in particular, for heart failure. Further, higher Gal-3 levels are associated with increased cardiovascular mortality. Whether Gal-3 is related with the protective effects of a high CRF is unclear. Purpose The present study examined the relation between Gal-3 and CRF as determined by body weight adjusted peak oxygen uptake (VO2peak/kg), oxygen uptake at the anaerobic threshold (VO2@AT) and maximal workload (Wmax). Methods We used data of the population-based Study of Health in Pomerania (SHIP-TREND) from Northeast Germany. A total of n = 1,483 participants with a median age of 49 (IQR: 39 – 59 years, male 48%) were included in the analysis. CRF parameters were measured using standardized cardiopulmonary exercise testing on a bicycle ergometer. Plasma galectin-3 concentrations were determined using a quantitative sandwich enzyme immunoassay. Individuals with left ventricular ejection fraction &lt; 40%, previous myocardial infarction, atrial fibrillation, chronic lung disease, severe renal disease (eGFR &lt; 30 ml/min/mm2), a history of cancer, and extreme values for Gal-3 were excluded. Linear regression models adjusted for age, sex and lean mass were used to analyze the association between Gal-3 and CRF. Results A one ml/min/kg greater VO2peak was related to a 0.32 ng/ml (95% confidence interval [CI] -0.45 to -0.18, p &lt;.001) lower Gal-3. Further, a one Watt larger power output was also associated with a 1.32 ng/ml (95% CI -2.10 to – 0.54, p &lt;.001) lesser Gal-3. VO2@AT was not related to Gal-3 (β: -3.31 95% CI -8.68 to 2.05, p = .23). Conclusions In the general population Gal-3 is inversely associated with CRF. Further studies should investigate whether lower Gal-3, beyond its importance as a biomarker for heart disease, may even play a role in the protective effect of the CRF.

Hollywood Rules

2017 ◽  
pp. 1-9
Author(s):  
Karl Schmedders ◽  
Charlotte Snyder ◽  
Ute Schaedel
Keyword(s):  
Confidence Intervals ◽  
Statistical Methods ◽  
Regression Models ◽  
Functional Form ◽  
Hedge Fund ◽  
Fund Manager ◽  
Wall Street ◽  
Independent Variables ◽  
Point Estimates ◽  
Hedge Fund Manager

Wall Street hedge fund manager Kim Meyer is considering investing in an SFA (slate financing arrangement) in Hollywood. Dave Griffith, a Hollywood producer, is pitching for the investment and has conducted a broad analysis of recent movie data to determine the important drivers of a movie’s success. In order to convince Meyer to invest in an SFA, Griffith must anticipate possible questions to maximize his persuasiveness.Students will analyze the factors driving a movie’s revenue using various statistical methods, including calculating point estimates, computing confidence intervals, conducting hypothesis tests, and developing regression models (in which they must both choose the relevant set of independent variables as well as determine an appropriate functional form for the regression equation). The case also requires the interpretation of the quantitative findings in the context of the application.

scholarly journals Statistical reporting in the "Clujul-Medical" journal

2015 ◽  
Vol 88 (4) ◽  
pp. 483-488
Author(s):  
Daniel-Corneliu Leucuța ◽  
Tudor Drugan ◽  
Andrei Achimaș
Keyword(s):  
Medical Journal ◽  
Medical Research ◽  
Confidence Intervals ◽  
Statistical Test ◽  
Statistical Analyses ◽  
Research Needs

Background and aim. Medical research needs statistical analyses to understand the reality of variable phenomena. There are numerous studies showing poor statistical reporting in many journals with different rankings, in different countries. Our aim was to assess the reporting of statistical analyses in original papers published in Clujul Medical journal in the year 2014.Methods. All original articles published in Clujul Medical in the year 2014 were assessed using mainly Statistical Analyses and Methods in the Published Literature guidelines.Results. The most important issues found in reporting statistical analyses were reduced reporting of:  assumptions checking, difference between groups or measures of associations, confidence intervals for the primary outcomes, and errors in the statistical test choice or the descriptive statistic choice for several analyses. These results are similar with other studies assessing different journals worldwide.Conclusion. Statistical reporting in Clujul Medical, like in other journals, have to be improved. 

Editorial Code for Presentation of Statistical Analyses

1994 ◽  
Vol 30 (4) ◽  
pp. 377-380 ◽  
Author(s):  
D. J. Finney ◽  
J. L. Harper
Keyword(s):  
Statistical Methods ◽  
Statistical Analyses

The proliferation of statistical methods and software increases the need for authors to state, unambiguously and informatively, the methods they have used. The reader of any paper should expect to learn precisely what the author has done, and to be able to adopt similar procedures in his or her own work.

scholarly journals Spatial and spatio-temporal statistical analyses of retinal images: a review of methods and applications

2020 ◽  
Vol 5 (1) ◽  
pp. e000479
Author(s):  
Wenyue Zhu ◽  
Ruwanthi Kolamunnage-Dona ◽  
Yalin Zheng ◽  
Simon Harding ◽  
Gabriela Czanner
Keyword(s):  
Statistical Methods ◽  
Spatial Data ◽  
Temporal Analysis ◽  
Statistical Analyses ◽  
Retinal Images ◽  
Imaging Data ◽  
Spatial Correlations ◽  
Clinical Variables ◽  
Text Information ◽  
Spatio Temporal

BackgroundClinical research and management of retinal diseases greatly depend on the interpretation of retinal images and often longitudinally collected images. Retinal images provide context for spatial data, namely the location of specific pathologies within the retina. Longitudinally collected images can show how clinical events at one point can affect the retina over time. In this review, we aimed to assess statistical approaches to spatial and spatio-temporal data in retinal images. We also review the spatio-temporal modelling approaches used in other medical image types.MethodsWe conducted a comprehensive literature review of both spatial or spatio-temporal approaches and non-spatial approaches to the statistical analysis of retinal images. The key methodological and clinical characteristics of published papers were extracted. We also investigated whether clinical variables and spatial correlation were accounted for in the analysis.ResultsThirty-four papers that included retinal imaging data were identified for full-text information extraction. Only 11 (32.4%) papers used spatial or spatio-temporal statistical methods to analyse images, others (23 papers, 67.6%) used non-spatial methods. Twenty-eight (82.4%) papers reported images collected cross-sectionally, while 6 (17.6%) papers reported analyses on images collected longitudinally. In imaging areas outside of ophthalmology, 19 papers were identified with spatio-temporal analysis, and multiple statistical methods were recorded.ConclusionsIn future statistical analyses of retinal images, it will be beneficial to clearly define and report the spatial distributions studied, report the spatial correlations, combine imaging data with clinical variables into analysis if available, and clearly state the software or packages used.

The P Value Problem in Otolaryngology: Shifting to Effect Sizes and Confidence Intervals

2016 ◽  
Vol 156 (6) ◽  
pp. 978-980 ◽  
Author(s):  
Peter M. Vila ◽  
Melanie Elizabeth Townsend ◽  
Neel K. Bhatt ◽  
W. Katherine Kao ◽  
Parul Sinha ◽  
...  
Keyword(s):  
General Population ◽  
Confidence Intervals ◽  
Clinical Significance ◽  
Paradigm Shift ◽  
Biomedical Literature ◽  
Effect Sizes ◽  
P Value ◽  
P Values ◽  
Population Mean

There is a lack of reporting effect sizes and confidence intervals in the current biomedical literature. The objective of this article is to present a discussion of the recent paradigm shift encouraging the use of reporting effect sizes and confidence intervals. Although P values help to inform us about whether an effect exists due to chance, effect sizes inform us about the magnitude of the effect (clinical significance), and confidence intervals inform us about the range of plausible estimates for the general population mean (precision). Reporting effect sizes and confidence intervals is a necessary addition to the biomedical literature, and these concepts are reviewed in this article.

Presenting Medical Statistics from Proposal to Publication

2013 ◽  
Author(s):  
Janet Peacock ◽  
Sally Kerry
Keyword(s):  
Statistical Methods ◽  
Journal Article ◽  
Real Data ◽  
Statistical Analyses ◽  
Medical Statistics ◽  
Wide Range ◽  
Good Presentation

Presenting Medical Statistics includes a wide range of statistical analyses, and all the statistical methods are illustrated using real data. Labelled figures show the Stata and SPSS commands needed to obtain the analyses, with indications of which information should be extracted from the output for reporting. The relevant results are then presented as for a report or journal article, to illustrate the principles of good presentation.

The Merits of Confidence Intervals Relative to Hypothesis Testing

1992 ◽  
Vol 13 (9) ◽  
pp. 553-555 ◽  
Author(s):  
Leon F. Burmeister ◽  
David Bimbaum ◽  
Samuel B. Sheps
Keyword(s):  
Hypothesis Testing ◽  
Confidence Intervals ◽  
Null Hypothesis ◽  
Finite Population ◽  
Extreme Values ◽  
Statistical Tests ◽  
Point Estimate ◽  
Distributed Data ◽  
Average Difference ◽  
Average Value

A variety of statistical tests of a null hypothesis commonly are used in biomedical studies. While these tests are the mainstay for justifying inferences drawn from data, they have important limitations. This report discusses the relative merits of two different approaches to data analysis and display, and recommends the use of confidence intervals rather than classic hypothesis testing.Formulae for a confidence interval surrounding the point estimate of an average value take the form: d= ±zσ/√n, where “d” represents the average difference between central and extreme values, “z” is derived from the density function of a known distribution, and “a/-∨n” represents the magnitude of sampling variability. Transposition of terms yields the familiar formula for hypothesis testing of normally distributed data (without applying the finite population correction factor): z = d/(σ/√n).

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