نتایج جستجو برای: variable sample size and sampling interval vssi control charts

تعداد نتایج: 17113236  

Journal: :Communications in Statistics - Simulation and Computation 2014
Seyed Taghi Akhavan Niaki Fazlollah Masoumi Gazaneh Moslem Toosheghanian

Among innovations and improvements occurred in the past two decades on the techniques and tools used for statistical process control (SPC), adaptive control charts have shown to substantially improve the statistical and/or economical performances. Variable sampling intervals (VSI) control charts are one of the most applied types of the adaptive control charts and have shown to be faster than tr...

Journal: :Systematic biology 2002
Derrick J Zwickl David M Hillis

Several authors have argued recently that extensive taxon sampling has a positive and important effect on the accuracy of phylogenetic estimates. However, other authors have argued that there is little benefit of extensive taxon sampling, and so phylogenetic problems can or should be reduced to a few exemplar taxa as a means of reducing the computational complexity of the phylogenetic analysis....

Journal: :Journal of environmental monitoring : JEM 2009
Elena Gottardini Fabiana Cristofolini Antonella Cristofori Arianna Vannini Marco Ferretti

Information about airborne pollen concentration is of concern for health authorities across Europe. The reliability of data estimates depends on the accuracy and precision of pollen counts. In Italy, pollen counts are carried out on slides for microscopic evaluation and are regulated by the national Standard UNI 11108:2004. Our results showed that counts performed according to the Italian stand...

2008
Robert DeSerio

Data obtained through measurement always contain random error. Random error is readily observed by sampling—making repeated measurements while all experimental conditions remain the same. For various reasons, the measurements will not all be the same and a frequency distribution (see Fig. 1) is one way to display the resulting data. The height of each vertical bar indicates the number of times ...

Journal: :Preventive veterinary medicine 2002
Thomas B Farver

A comparison was made of three small-area sampling methods [two traditional design-based methods (ratio-synthetic, sample-size dependent) and one model-based method (EBLUP)] in estimation of some cow and sow population productivity parameters. Performance was evaluated in estimating both farm-specific mean responses and mean animal response over all farms using sample sizes of 100 and 25. Diffe...

Journal: :Molecular biology and evolution 2006
Joseph Felsenstein

A computer simulation study has been made of the accuracy of estimates of Theta = 4Nemu from a sample from a single isolated population of finite size. The accuracies turn out to be well predicted by a formula developed by Fu and Li, who used optimistic assumptions. Their formulas are restated in terms of accuracy, defined here as the reciprocal of the squared coefficient of variation. This sho...

Journal: :Revista brasileira de epidemiologia = Brazilian journal of epidemiology 2013
Rita Barradas Barata Susan M Pereira

OBJECTIVE To estimate the vaccination coverage in children born in the city of Salvador, analyzing these coverages by socioeconomic conditions. METHOD A household survey on vaccination coverage was conducted with children born in 2005, in Salvador, Bahia, northeastern Brazil, who were aged between 18 to 36 months at the time of this study. Cluster sampling was performed in multiple stages. Ce...

2016
Juha Pajula Jussi Tohka

Inter-subject correlation (ISC) is a widely used method for analyzing functional magnetic resonance imaging (fMRI) data acquired during naturalistic stimuli. A challenge in ISC analysis is to define the required sample size in the way that the results are reliable. We studied the effect of the sample size on the reliability of ISC analysis and additionally addressed the following question: How ...

2007
S. Psarakis J. Panaretos

The Shewhart and the Bonferroni-adjustment S control charts are usually applied to monitor the standard deviation of a quality characteristic. The control limits of these charts are constructed using approximately the normal distribution in case that the standard deviation parameter is known or unknown. In this paper, we establish a new S chart that is based approximately on the normal distribu...

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