Search results for "table"
showing 10 items of 2807 documents
III: „Relatives Risiko” und „NNT” - anschauliche Maße für binäre Daten
2002
Description of categorial data can often be based on contingency tables. However, percentages appearing in such tables must be meaningful: For most applications, it may be useful to employ factors of causal influence as the row entry variable and relate percentages to sub-groups defined by these row entries ("row percentages"). The comparison of success frequencies (i. e. binary information on "therapy success yes/no") may be based on two therapies, respective success frequencies and their ratio, the relative risk. In addition the success frequencies' difference, the absolute (or excess) risk, can be transformed into the "number needed to treat" (NNT). Many international journals demand thi…
Collapsibility and Collapsing Multidimensional Contingency Tables—Perspectives and Implications
2000
Collapsing multidimensional contingency tables is a necessary procedure in all kinds of research. Since collapsibility is subject to severe conditions, collapsing is often not admissible without incurring severe interpretative errors. After having discussed the main contributions to the statistical specification of the concept, we shall point out the logical conditions for collapsing multidimensional contingency tables.
Utility of the Mantel-Haenszel Procedure for Detecting Differential Item Functioning in Small Samples
2004
Sample-size restrictions limit the contingency table approaches based on asymptotic distributions, such as the Mantel-Haenszel (MH) procedure, for detecting differential item functioning (DIF) in many practical applications. Within this framework, the present study investigated the power and Type I error performance of empirical and inferential criteria for DIF detection in small samples. Sample sizes (50/50, 100/50, 200/50, and 100/100 for the reference and focal groups, respectively), ability distributions (equal and unequal), and amount of DIF (moderate and high) were manipulated. The results show the advantages of employing theMHchi-square statistic using high levels of significance (•…
Testing the group polarization hypothesis by using logit models
2002
This paper focuses on methodological aspects of group polarization research and has two well-defined parts. The first part presents a methodological overview of group polarization research together with an examination of the inadequacy, under certain circumstances, of the traditional parametric approach usually used to test this phenomenon based on pre-test/post-test means comparison across groups. It is shown that this approach will produce masks effects when groups are heterogeneous with regard to the observed change from pre-test to post-test. The second part suggests an alternative methodological approach based on logit models for the analysis of contingency tables from a categorization…
Continuity correction of pearson’s chi-square test in 2x2 contingency tables: A mini-review on recent development
2022
The Pearson’s chi-square test represents a nonparametric test more used in Biomedicine and Social Sciences, but it introduces an error for 2 x 2 contingency tables, when a discrete probability distribution is approximated with a continuous distribution. The first author to introduce the continuity correction of Pearson’s chi-square test has been Yates F. (1934). Unfortunately, Yates’s correction may tend to overcorrect of p-value, this can implicate an overly conservative result. Therefore many authors have introduced variants Pearson’s chi-square statistic, as alternative continuity correction to Yates’s correction. The goal of this paper is to describe the most recent continuity correctio…
Interim 18f-PDGPET for Aggressive Non-Hodgking's Lymphoma: A Systematic Review and Meta-Analysis
2011
Abstract Abstract 5183 Background: The advantage of using interim 18F-fluorodeoxyglucose (FDG) positron-emission tomography (PET) scan in the clinical work-up of patients with non-Hodgkin's lymphoma (NLH) is unclear. Data from meta-analyses are inconclusive, mainly because of the low number of patients evaluated and heterogeneity among studies. New clinical investigations, focused on this topic, have been recently published. We conducted an updated systematic review on the role of 18PDG-PET for the interim evaluation in patients with aggressive lymphomas. Materials and Methods: Medline, Embase, Scopus and Databases were searched for relevant studies through March 2011. We included studies t…
Role of conditional probability in multiscale stationary markovian processes.
2010
The aim of the paper is to understand how the inclusion of more and more time-scales into a stochastic stationary Markovian process affects its conditional probability. To this end, we consider two Gaussian processes: (i) a short-range correlated process with an infinite set of time-scales bounded from below, and (ii) a power-law correlated process with an infinite and unbounded set of time-scales. For these processes we investigate the equal position conditional probability P(x,t|x,0) and the mean First Passage Time T(L). The function P(x,t|x,0) can be considered as a proxy of the persistence, i.e. the fact that when a process reaches a position x then it spends some time around that posit…
A General Mathematical Formulation for Winding Layout Arrangement of Electrical Machines
2018
Winding design methods have been a subject of research for many years of the past century. Many methods have been developed, each one characterized by some advantages and drawbacks. Nowadays, the star of slots is the most widespread design tool for electrical machine windings. In this context, this paper presents a simple and effective procedure to determine the distribution of the slot EMFs over the phases and of the winding configuration in all possible typologies of electrical machines equipped with symmetrical windings. The result of this procedure gives a Winding Distribution Table (WDT), which can be used to define coils and coil groups connections and also to simply implement winding…
Improvement of plum storage with modified atmosphere packaging
2010
Post-harvest supply chain is a critical point for agro-food marketing. The management of freshness in the storage is fundamental to maintain high profits in the agro-food sector to improve the distribution and to respond to retailers and consumers' requirements. Plums are considered to have a climacteric-ripening pattern, in which ethylene is the hormone responsible for ripening. Modified atmosphere (MA) storage is a method helpful to maintain the natural quality of fruits. MA added to low temperatures influence fruit metabolism and reduce ethylene production, weight losses, hardness of pulp, preserving vitamins and organic acids. The objective of this study was to increase the condition of…
Management et contrôle de gestion : DSCG épreuve 3 : manuel, applications & corrigés
2012
National audience; ...