The Control of Proportion Defective as Judged by a Single Quality Characteristic Varying on a Continuous Scale

1939 ◽  
Vol 6 (1) ◽  
pp. 80 ◽  
Author(s):  
W. J. Jennett ◽  
B. L. Welch
2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Geetha Sathya Narayanan ◽  
Vijayaraghavan Rajarathinam

Product control in statistical quality control is the methodology that deals with procedures for taking decisions about one or more lots of finished products manufactured by production processes. Sampling inspection by variables is one of the major classifications of product control and comprises procedures for deciding about the disposition of a lot of individual units based on sample measurements of units on a quality characteristic under study. These procedures are defined under the assumption that the quality characteristic is measurable on a continuous scale, and the functional form of the probability distribution must be known. Inspection procedures which have been developed under the implicit assumption that the quality characteristic is distributed as normal with the related properties are found in the literature of product control. The assumption of normality may not be realized often in practice, and it becomes indispensable to investigate the properties of sampling plans based on nonnormal distributions. In this paper, a single sampling plan by variables is formulated and evaluated when the quality characteristic is assumed to be distributed according to a Pareto distribution. A procedure is developed for determining the parameters of the plan for specified requirements to ensure protection to both the producer and consumer.


2020 ◽  
Author(s):  
Medha Shekhar ◽  
Dobromir Rahnev

Humans have the metacognitive ability to judge the accuracy of their own decisions via confidence ratings. A substantial body of research has demonstrated that human metacognition is fallible but it remains unclear how metacognitive inefficiency should be incorporated into a mechanistic model of confidence generation. Here we show that, contrary to what is typically assumed, metacognitive inefficiency depends on the level of confidence. We found that, across five different datasets and four different measures of metacognition, metacognitive ability decreased with higher confidence ratings. To understand the nature of this effect, we collected a large dataset of 20 subjects completing 2,800 trials each and providing confidence ratings on a continuous scale. The results demonstrated a robustly nonlinear zROC curve with downward curvature, despite a decades-old assumption of linearity. This pattern of results was reproduced by a new mechanistic model of confidence generation, which assumes the existence of lognormally-distributed metacognitive noise. The model outperformed competing models either lacking metacognitive noise altogether or featuring Gaussian metacognitive noise. Further, the model could generate a measure of metacognitive ability which was independent of confidence levels. These findings establish an empirically-validated model of confidence generation, have significant implications about measures of metacognitive ability, and begin to reveal the underlying nature of metacognitive inefficiency.


2009 ◽  
Vol 38 (7) ◽  
pp. 902-908 ◽  
Author(s):  
In-Bae Park ◽  
Jeong-Wook Park ◽  
Young-Jae Lee ◽  
Gung-Won Shin ◽  
Hae-Seop Kim ◽  
...  

Mathematics ◽  
2021 ◽  
Vol 9 (10) ◽  
pp. 1076
Author(s):  
Wei Lo ◽  
Chun-Ming Yang ◽  
Kuei-Kuei Lai ◽  
Shao-Yu Li ◽  
Chi-Han Chen

When all of the one-sided specification indices of each quality characteristic reach the requirements of the process quality level, they can ensure that the process capability of the product meets the requirements of the process quality level. This study constructs a fuzzy membership function based on the upper confidence limit of the index, derives the fuzzy critical value, and then labels the fuzzy critical value on the axis of the visualized radar chart as well as connects adjacent critical points to shape a regular polygonal critical region. Next, this study calculates the observed value of the index to estimate and mark it on the axis for forming a visualized fuzzy radar evaluation chart. Obviously, this fuzzy evaluation model not only reduces the testing cost but also makes the quality level quickly meet the requirements of the specifications. Further, the radar chart can reduce the risk of misjudgment attributable to sampling errors and help improve the accuracy of evaluation by a confidence-upper-limit-based fuzzy evaluation model. Therefore, this easy-to-use visualized fuzzy radar evaluation chart is used as an evaluation interface, which has good and convenient management performance to identify and improve critical-to-quality quickly. Improving the quality of the process before the product is completed will also have the advantage of reducing social losses and environmental damage costs.


Author(s):  
Verena Gotta ◽  
Olivera Marsenic ◽  
Andrew Atkinson ◽  
Marc Pfister

Abstract Background Hemodialysis (HD) dose targets and ultrafiltration rate (UFR) limits for pediatric patients on chronic HD are not known and are derived from adults (spKt/V>1.4 and <13 ml/kg/h). We aimed to characterize how delivered HD dose and UFR are associated with survival in a large cohort of patients who started HD in childhood. Methods Retrospective analysis on a cohort of patients <30 years, on chronic HD since childhood (<19 years), having received thrice-weekly HD 2004–2016 in outpatient DaVita centers. Outcome: Survival while remaining on HD. Predictors: (I) primary analysis: mean delivered dialysis dose stratified as spKt/V ≤1.4/1.4–1.6/>1.6 (Kaplan–Meier analysis), (II) secondary analyses: UFR and alternative dialysis adequacy measures [eKt/V, body-surface normalized Kt/BSA] on continuous scale (Weibull regression model). Results A total of 1780 patients were included (age at the start of HD: 0–12y: n=321, >12–18y: n=1459; median spKt/V=1.55, eKt/V=1.31, Kt/BSA=31.2 L/m2, UFR=10.6 mL/kg/h). (I) spKt/V<1.4 was associated with lower survival compared to spKt/V>1.4–1.6 (P<0.001, log-rank test), and spKt/V>1.6 (P<0.001), with 10-year survival of 69.3% (59.4–80.9%) versus 83.0% (76.8–89.8%) and 84.0% (79.6–88.5%), respectively. (II) Kt/BSA was a better predictor of survival than spKt/V or eKt/V. UFR was additionally associated with survival (P<0.001), with increased mortality <10/>18 mL/kg/h. Associations did not alter significantly following adjustment for demographic characteristics (age, etiology of kidney disease, and ethnicity). Conclusions Our results suggest usefulness of targeting Kt/BSA>30 L/m2 for best long-term outcomes, corresponding to spKt/V>1.4 (>12 years) and >1.6 (<12 years). In contrast to adults, higher UFR of 10–18 ml/kg/h was not associated with greater mortality in this population.


2020 ◽  
Vol 71 (10) ◽  
pp. 884
Author(s):  
Zhikun Wang ◽  
Mingming Yang ◽  
Yuanzhuo Wang ◽  
Chao Yang ◽  
Xue Zhao ◽  
...  

Association analysis is an alternative to conventional, family-based methods for detecting the location of gene(s) or quantitative trait loci (QTLs), and provides relatively high resolution in terms of defining the genome position of a gene or QTL. Flavour is an essential quality characteristic of soymilk; however, soymilk contains volatile compounds unacceptable to consumers. One of main constituents in the volatiles of normal soymilk is 2-heptenal, which is thought to be a degradative oxidation product of polyunsaturated acids. In this study, a genome-wide association study using 24651 single-nucleotide polymorphisms (SNPs) was performed to identify quantitative trait nucleotides (QTNs) controlling 2-heptenal content in soybean (Glycine max (L.) Merr.) seed from a natural population of 110 soybean germplasm accessions. We detected 62 significant QTNs located on 18 different chromosomes that are significantly associated with 2-heptenal content in soybean seed. Among these, 17 QTNs co-localised with QTLs previously found to be related to protein, oil and/or fatty acid content in soybean seed. We also identified some candidate genes involved in lipid metabolism. These findings further our understanding of the genetic basis of 2-heptenal content in soybean seed and the improvement of marker-assisted breeding efficiency, which will be important for breeding soybean cultivars with low 2-heptenal content.


2006 ◽  
Vol 86 (11) ◽  
pp. 1479-1488 ◽  
Author(s):  
Lynn B Panton ◽  
J Derek Kingsley ◽  
Tonya Toole ◽  
M Elaine Cress ◽  
George Abboud ◽  
...  

Abstract Background and Purposes. The purpose of this study was to compare functionality and strength among women with fibromyalgia (FM), women without FM, and older women. Subjects. Twenty-nine women with FM (age [X̅±SD]=46±7 years), 12 age- and weight-matched women without FM (age=44±8 years), and 38 older women who were healthy (age=71±7 years) participated. Methods. The Continuous Scale–Physical Functional Performance Test (CS-PFP) was used to assess functionality. Isokinetic leg strength was measured at 60°/s, and handgrip strength was measured using a handgrip dynamometer. Results. The women without FM had significantly higher functionality scores compared with women with FM and older women. There were no differences in functionality between women with FM and older women. Strength measures for the leg were higher in women without FM compared with women with FM and older women, and both women with and without FM had higher grip strengths compared with older women. Discussion and Conclusion. This study demonstrated that women with FM and older women who are healthy have similar lower-body strength and functionality, potentially enhancing the risk for premature age-associated disability.


2004 ◽  
Vol 21 (Supplement 32) ◽  
pp. 190-191
Author(s):  
C. Gaetano ◽  
T. Saverio ◽  
D. I. Tommaso ◽  
V Michelangelo ◽  
D. A. Margherita ◽  
...  
Keyword(s):  

2009 ◽  
Vol 16 (2) ◽  
pp. 228-237 ◽  
Author(s):  
AS Drake ◽  
B. Weinstock-Guttman ◽  
SA Morrow ◽  
D. Hojnacki ◽  
FE Munschauer ◽  
...  

The MS Functional Composite (MSFC) is a continuous scale of neurological disability for patients with multiple sclerosis (MS). Cognition is represented by the Paced Auditory Serial Addition Test (PASAT), although the Symbol Digit Modalities Test (SDMT) has been proposed as a promising alternative. MSFC scores were calculated using either the PASAT or the SDMT with the following reference populations: National Multiple Sclerosis Society (NMSS) Task Force, 400 MS patients, and 100 normal controls. A subgroup of 115 patients was followed longitudinally, with a test—retest interval of 2.3 ± 1.2 years. Pearson correlations were calculated and analyses of variance (ANOVAs) were used to assess relationships among the MSFC components and composite scores, and differences in performance between patients and controls. Longitudinal changes were also assessed. Logistic regression was performed to determine which MSFC scores are most predictive of diagnosis, course, and work disability. All MSFCs had similar test—retest reliability and correlations with other measures including neurological disability, depression, and fatigue. The SDMT showed slightly better validity with respect to predicting diagnosis, course, and work disability, although the amount of variance accounted for was similar for each version of the MSFC. Our data, derived from a large sample of MS patients and normal controls, supports the validity of both PASAT and SDMT versions of the MSFC. Because the SDMT has slightly better predictive validity and has a relatively easier administration procedure, some clinicians and researchers may wish to replace the PASAT with the SDMT in future calculations of the MSFC using the calculation methods provided in this manuscript.


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