Search results for "chi-square test"
showing 10 items of 34 documents
Significance of pre-treatment panoramic radiographic assessment of edentulous patients-A survey
2010
Objectives: The present study was undertaken to review the significance of pre-treatment panoramic radiographic assessment of edentulous patients, in the dental patient population of Haryana, India. Study Design: In this study a total of 525 completely edentulous patients were selected randomly. A panoramic radiograph was taken using Panoramic machine (Rotagraph plus) and all the radiographs were evaluated by 2 oral radiology specialists for the following clinically significant radiographic findings: retained root fragments, embedded teeth, radiolucencies, radiopacities and location of the mental foramen at the crest of the residual alveolar ridge. The data were analyzed using the chi squar…
T2 Mapping of the Sacroiliac Joints in Patients with Axial Spondyloarthritis
2020
Purpose: To test whether T2 mapping of the sacro-iliac joints (SIJs) might help identifying patients with spondyloarthritis. Method: This study included 20 biologic-naive patients with axial spondyloarthritis (10 females; mean age: 38 ± 9years; range, 19–47) and 27 controls (16 males; mean age = 39 ± 13years; range = 28–71) who prospectively underwent SIJs MRI at 1.5 T, including a multislice multiecho spin-echo sequence. Standard MRIs were reviewed to assess the SIJs according to the Assessment of SpondyloArthritis International Society (ASAS) criteria and SPondyloArthritis Research Consortium of Canada (SPARCC) MRI index. T2 maps obtained from multiecho sequences were used to draw regions…
Differences between orthopaedic evaluation and radiological reports of conventional radiographs in patients with minor trauma admitted to the emergen…
2017
Abstract Introduction During night and on weekends, in our emergency department there is no radiologist on duty or on call: thus, X-ray examinations (XR) are evaluated by the orthopaedic surgeon on duty and reported the following morning/monday by radiologists. The aim of our study was to examine the discrepancy rate between orthopaedists and radiologists in the interpretation of imaging examinations performed on patients in our tertiary level orthopaedic institution and the consequences of delayed diagnosis in terms of patient management and therapeutic strategy. Materials and methods We retrospectively reviewed all cases of discrepancy between orthopaedists and radiologists, which were ca…
Is it necessary to alter anticoagulation therapy for tooth extraction in patients taking direct oral anticoagulants?
2017
Background The number of patients using direct oral anticoagulants (DOACs) instead of vitamin K antagonists (VKA) is increasing and there is limited data on the safety of tooth extractions in patients taking DOACs. The aim of this study was to compare the amount of bleeding (AOB) and postoperative complications after tooth extractions between patients taking VKAs and patients taking DOACs without altering the anticoaguation therapy. Material and Methods The study consisted of four groups: Direct thrombin inhibitor group, factor Xa inhibitor group, warfarin group and a control group. A single tooth was extracted in each patient and routine coagulation test values were recorded prior to extra…
Automatic regrouping of strata in the goodness-of-fit chi-square test
2019
Pearson’s chi-square test is widely employed in social and health sciences to analyze categorical data and contingency tables. For the test to be valid, the sample size must be large enough to provide a minimum number of expected elements per category. This paper develops functions for regrouping strata automatically no matter where they are located, thus enabling the goodness-of-fit test to be performed within an iterative procedure. The functions are written in Excel VBA (Visual Basic for Applications) and in Mathematica. The usefulness and performance of these functions is illustrated by means of a simulation study and the application to different datasets. Finally, the iterative use of …
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…
Participation Profiles and Socialisation into Dance Among Non‐Professional Dancers
1997
Abstract The study was designed to determine how individuals become socialised into folk, competitive ballroom, ballet and modern dance through an investigation of background variables, the influence of significant others and the participation profiles of dancers, and the identification of those socialization and involvement variables that best discriminate among different groups of dancers. The subjects were 308 adolescent and adult dancers of at least 16 years of age who had pursued their main dance form for a minimum of three years. The data were collected by questionnaire, supplemented with some additional data gathered through personal interviews. Differences between the four dance gro…
A Procedure for Selecting Representative Subsamples of a Population from a Simple Random Sample
2015
This paper proposes a procedure for selecting large subsamples drawn from a large simple random sample that are more representative of the population under study. By means of the so-called constant of proportionality, the procedure seeks to maximize the size of the subsample taken from a stratified random sample with proportional allocation, restricting it to a p-value high enough to achieve a good fit using Pearson’s chi-square goodness of fit test. The user has the freedom to choose between a larger subsample with poorer adjustment or a smaller subsample with a better fit. We use the Continuous Sample of Working Lives (CSWL), a set of micro data taken from Spanish Social Security records,…
Improving the Representativeness of a Simple Random Sample: An Optimization Model and Its Application to the Continuous Sample of Working Lives
2020
This paper proposes an optimization model for selecting a larger subsample that improves the representativeness of a simple random sample previously obtained from a population larger than the population of interest. The problem formulation involves convex mixed-integer nonlinear programming (convex MINLP) and is, therefore, NP-hard. However, the solution is found by maximizing the size of the subsample taken from a stratified random sample with proportional allocation and restricting it to a p-value large enough to achieve a good fit to the population of interest using Pearson&rsquo
On the moments of Cochran's Q statistic under the null hypothesis, with application to the meta-analysis of risk difference.
2011
W. G. Cochran's Q statistic was introduced in 1937 to test for equality of means under heteroscedasticity. Today, the use of Q is widespread in tests for homogeneity of effects in meta-analysis, but often these effects (such as risk differences and odds ratios) are not normally distributed. It is common to assume that Q follows a chi-square distribution, but it has long been known that this asymptotic distribution for Q is not accurate for moderate sample sizes. In this paper, the effect and weight for an individual study may depend on two parameters: the effect and a nuisance parameter. We present expansions for the first two moments of Q without any normality assumptions. Our expansions w…