EVALUATION OF THE ARROWS METHOD FOR CLASSIFICATION OF DATA

2010 ◽  
Vol 27 (01) ◽  
pp. 121-142 ◽  
Author(s):  
LANTING LU ◽  
CHRISTINE S. M. CURRIE
Keyword(s):  
Goodness Of Fit ◽  
Assembly Line ◽  
P Value ◽  
Practical Application ◽  
P Values ◽  
Conflicting Objectives ◽  
Technical Details ◽  
Simulation Input ◽  
Von Mises

We evaluate the Arrows Classification Method (ACM) for grouping objects based on the similarity of their data. This is a new method, which aims to achieve a balance between the conflicting objectives of maximizing internal cohesion and external isolation in the output groups. The method is widely applicable, especially in simulation input and output modelling, and has previously been used for grouping machines on an assembly line, based on data on time-to-repair; and hospital procedures, based on length-of-stay data. The similarity of the data from a pair of objects is measured using the two-sample Cramér-von-Mises goodness of fit statistic, with bootstrapping employed to find the significance or p-value of the calculated statistic. The p-values coming from the paired comparisons serve as inputs to the ACM, and allow the objects to be classified such that no pair of objects that are grouped together have significantly different data. In this article, we give the technical details of the method and evaluate its use through testing with specially generated samples. We will also demonstrate its practical application with two real examples.

The Conundrum of P-Values: Statistical Significance is Unavoidable but Need Medical Significance Too

2020 ◽  
Author(s):  
Abhaya Indrayan
Keyword(s):  
Type I Error ◽  
Dominant Role ◽  
Statistical Significance ◽  
Empirical Studies ◽  
P Value ◽  
Selective Reporting ◽  
Type I ◽  
Practical Application ◽  
P Values ◽  
Zero Effect

Background: Small P-values have been conventionally considered as evidence to reject a null hypothesis in empirical studies. However, there is widespread criticism of P-values now and the threshold we use for statistical significance is questioned.Methods: This communication is on contrarian view and explains why P-value and its threshold are still useful for ruling out sampling fluctuation as a source of the findings.Results: The problem is not with P-values themselves but it is with their misuse, abuse, and over-use, including the dominant role they have assumed in empirical results. False results may be mostly because of errors in design, invalid data, inadequate analysis, inappropriate interpretation, accumulation of Type-I error, and selective reporting, and not because of P-values per se.Conclusion: A threshold of P-values such as 0.05 for statistical significance is helpful in making a binary inference for practical application of the result. However, a lower threshold can be suggested to reduce the chance of false results. Also, the emphasis should be on detecting a medically significant effect and not zero effect.

scholarly journals New relevance and significance measures to replace p-values

PLoS ONE ◽  
2021 ◽  
Vol 16 (6) ◽  
pp. e0252991
Author(s):  
Werner A. Stahel
Keyword(s):  
Null Hypothesis ◽  
Quantitative Measure ◽  
P Value ◽  
Fundamental Issue ◽  
P Values ◽  
Misleading Interpretation ◽  
Single Number ◽  
Relevance Measure ◽  
Significance Measures

The p-value has been debated exorbitantly in the last decades, experiencing fierce critique, but also finding some advocates. The fundamental issue with its misleading interpretation stems from its common use for testing the unrealistic null hypothesis of an effect that is precisely zero. A meaningful question asks instead whether the effect is relevant. It is then unavoidable that a threshold for relevance is chosen. Considerations that can lead to agreeable conventions for this choice are presented for several commonly used statistical situations. Based on the threshold, a simple quantitative measure of relevance emerges naturally. Statistical inference for the effect should be based on the confidence interval for the relevance measure. A classification of results that goes beyond a simple distinction like “significant / non-significant” is proposed. On the other hand, if desired, a single number called the “secured relevance” may summarize the result, like the p-value does it, but with a scientifically meaningful interpretation.

scholarly journals WHEN AND WHERE P-VALUE IS REQUIRED: MISNOMERS IN CLINICALAND STATISTICAL SIGNIFICANCE

2021 ◽  
pp. 1-2
Author(s):  
Sukhvinder Singh Oberoi ◽  
Mansi Atri
Keyword(s):  
Data Analysis ◽  
Confidence Intervals ◽  
Effect Size ◽  
Statistical Significance ◽  
Significance Testing ◽  
P Value ◽  
Practical Application ◽  
Statistical Software ◽  
P Values ◽  
Long Time

The interpretation of the p-value has been an arena for discussion making it difficult for many researchers. The p-value was introduced in 1900 by Pearson. Though, it is very difficult to comment about the demerits of the p-values and significance testing which has not been spoken in a long time because of the practical application of it as a measure of interpretation in clinical research. The usage of the confidence intervals around the sample statistics and effect size should be given more importance than relying solely upon the statistical significance. The researchers, should be consulting a statistician in the initial stages of the planning of the study for avoidance of the misinterpretation of the P-value especially if they are using statistical software for their data analysis.

FEATURES OF OPHTHALMIC CARE FOR PATIENTS WITH COMPLICATED CATARACTS

2020 ◽  
pp. 84-89
Author(s):  
Inna Ivanovna Lapkina
Keyword(s):  
Health Care ◽  
Surgical Treatment ◽  
Postoperative Complications ◽  
Key Words ◽  
Outpatient Treatment ◽  
Practical Application ◽  
Unified Approach ◽  
Case Histories ◽  
High Prevalence

Today, around 50 million people worldwide suffer from cataracts, more than a half of them need surgical treatment. High prevalence of this pathology in Ukraine, the need to improve the provision of ophthalmic care to patients, and the reform of the health care system have made the research relevant. Concomitant diseases and special conditions of the eye increase the risk of intra− and postoperative complications, worsen the functional parameters of patients after surgery. In order to develop a unified approach to the treatment of complicated cataracts based on diagnostically related groups of patients, a retrospective analysis of case histories of patients with different variants of complications related to the condition of the lens itself, its ligament apparatus and other structures of the eye was conducted. In each case, the surgeon has to choose the appropriate modification of cataract phacoemulsification surgery. The study proposed the classification of cataract phacoemulsification modifications on the basis of the techniques and the sequence of operation stages, taking into account the classification of the degrees of turbidity of the lens, proposed by L. Buratto. It has been noted that in complicated cases, according to the indications of the patient, surgery may be performed on several modifications of cataract phacoemulsification. The developed classification made it possible to generalize the various variants of pathology and greatly facilitate the choice of tactics of surgical treatment in complicated cataracts. It can be used not only for practical application, but also for improving the qualification of trained professionals. The prospect of further research is to identify contraindications for outpatient treatment of the patients with complicated cataracts. Key words: cataract complication, classification of phacoemulsification modifications, diagnostically related groups.

scholarly journals Dark energy survey internal consistency tests of the joint cosmological probes analysis with posterior predictive distributions

2021 ◽  
Vol 503 (2) ◽  
pp. 2688-2705
Author(s):  
C Doux ◽  
E Baxter ◽  
P Lemos ◽  
C Chang ◽  
A Alarcon ◽  
...  
Keyword(s):  
Dark Energy ◽  
Internal Consistency ◽  
Goodness Of Fit ◽  
Small Scale ◽  
P Value ◽  
Posterior Predictive Distribution ◽  
Data Set ◽  
Dark Energy Survey ◽  
Data Vector ◽  
Energy Survey

ABSTRACT Beyond ΛCDM, physics or systematic errors may cause subsets of a cosmological data set to appear inconsistent when analysed assuming ΛCDM. We present an application of internal consistency tests to measurements from the Dark Energy Survey Year 1 (DES Y1) joint probes analysis. Our analysis relies on computing the posterior predictive distribution (PPD) for these data under the assumption of ΛCDM. We find that the DES Y1 data have an acceptable goodness of fit to ΛCDM, with a probability of finding a worse fit by random chance of p = 0.046. Using numerical PPD tests, supplemented by graphical checks, we show that most of the data vector appears completely consistent with expectations, although we observe a small tension between large- and small-scale measurements. A small part (roughly 1.5 per cent) of the data vector shows an unusually large departure from expectations; excluding this part of the data has negligible impact on cosmological constraints, but does significantly improve the p-value to 0.10. The methodology developed here will be applied to test the consistency of DES Year 3 joint probes data sets.

scholarly journals SAT0210 FACTORS ASSOCIATED WITH TIME TO SEVERE LUPUS NEPHRITIS IN A COHORT OF COLOMBIAN PATIENTS

2020 ◽  
Vol 79 (Suppl 1) ◽  
pp. 1048.2-1048
Author(s):  
S. Herrera ◽  
J. C. Diaz-Coronado ◽  
D. Rojas-Gualdrón ◽  
L. Betancur-Vasquez ◽  
D. Gonzalez-Hurtado ◽  
...  
Keyword(s):  
Lupus Nephritis ◽  
Renal Involvement ◽  
Classification Criteria ◽  
P Value ◽  
Systemic Lupus ◽  
P Values ◽  
Interval Censored ◽  
Severe Lupus Nephritis ◽  
Age And Sex

Background:Systemic lupus erythematosus (SLE) clinical manifestations, and their severity, vary according to age, ethnicity and socioeconomic status. Both Hispanic and Afro-Americans have a higher incidence and more sever presentation when compared to Caucasian patients with SLEObjectives:To analyze clinical and immunological characteristics associated with time to severe renal involvement in patients with Systemic Lupus Erythematous in a Colombian cohort followed for one year, between January 2015 and December 2018Methods:Retrospective follow-up study based in clinical records. Patients with SLE diagnosis that fulfilled either 1987 American College of Rheumatology Classification Criteria for SLE or 2011 Systemic Lupus International Collaborating Clinics (SLICC) classification criteria for SLE. We included patients with diagnosis of lupus nephritis according to Wallace and Dubois criteria. Patients who did not have at least two follow-up measurements or had a cause of nephritis other than lupus were excluded. The main outcome was defined as time from diagnosis to sever renal involvement defined as creatinine clearance ≤50 ml/min, 24-hour proteinuria ≥3.5 grams o end stage renal disease.We analyzed clinical and immunological characteristics. Descriptive statistical analyses of participant data during the first evaluation are reported as frequencies and percentages for categorical variables, and as medians and interquartile ranges (IQR) for quantitative variables. Age and sex adjusted survival functions and Hazard ratios (HR) with 95% confidence intervals and p-values were estimated using parametric Weibull models por interval-censored data. P values < 0.05 were considered statistically significantResults:548 patients were analyzed: 67 were left-censored as they presented renal involvement at entry, 6 were interval censored as outcome occurred between study visits, and 475 were right-censored as involvement was not registered during follow-up. 529 (96.5%) patients were female, median age at entry was 46 (IQR = 23) and median age to diagnosis was 29.5 (IQR = 20.6). 67% were mestizo, 13% Caucasian and 0.3% Afro-Colombian. Age and sex adjusted variables associated with time to severe lupus nephritis were high blood pressure HR = 3.5 (95%CI 2.2-5.6; p-value <0.001) and Anti-RO (per unit increase) HR = 1.002 (95%CI 1.001-1.004; p-value = 0.04). Figure 1 shows age and sex adjusted survival function.Conclusion:In our cohort the appearance of severe lupus nephritis occurs in less than 15% of patients at 10 years. Both high blood pressure and elevated anti-Ro titers were associated with a higher rate of onset in the presentation of severe lupus nephritis, as seen in some polymorphs of anti Ro.References:Disclosure of Interests:Sebastian Herrera Speakers bureau: academic conference, Juan camilo Diaz-Coronado: None declared, Diego Rojas-Gualdrón: None declared, Laura Betancur-Vasquez: None declared, Daniel Gonzalez-Hurtado: None declared, Juanita Gonzalez-Arango: None declared, laura Uribe-Arango: None declared, Maria Fernanda Saavedra Chacón: None declared, Jorge Lacouture-Fierro: None declared, Santiago Monsalve: None declared, Sebastian Guerra-Zarama: None declared, Juan david Lopez: None declared, Juan david Serna: None declared, Julian Barbosa: None declared, Ana Sierra: None declared, Deicy Hernandez-Parra: None declared, Ricardo Pineda.Tamayo: None declared

A classification of assembly line balancing problems

2007 ◽  
Vol 183 (2) ◽  
pp. 674-693 ◽  
Author(s):  
Nils Boysen ◽  
Malte Fliedner ◽  
Armin Scholl
Keyword(s):  
Assembly Line ◽  
Assembly Line Balancing ◽  
Line Balancing
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