scholarly journals The application of orthogonal contrasts to determine homogeneous groups

2021 ◽  
Vol 82 ◽  
pp. 31-44
Author(s):  
Zbigniew Laudański ◽  
Dariusz Mańkowski ◽  
Leszek Sieczko ◽  
Monika Janaszek-Mańkowska
Keyword(s):  
Analysis Of Variance ◽  
Multiple Comparison ◽  
Factorial Designs ◽  
Homogeneous Groups ◽  
Orthogonal Contrasts ◽  
Multiple Comparison Procedure ◽  
Effective Use

The paper presents a modified approach to analysis of data obtained from experiments carried out according to classical factorial designs. Four examples were discussed in order to present details of proposed method. Modification of the analysis of variance presented here enables more effective use of information on how studied factors affect the means of dependent variable. The specificity of this approach is based on alternative multiple comparison procedure incorporating orthogonal contrasts to determine homogeneous groups.

A More Powerful Post Hoc Multiple Comparison Procedure in Analysis of Variance

1998 ◽  
Vol 23 (3) ◽  
pp. 279-289 ◽  
Author(s):  
Alan J. Klockars ◽  
Gregory R. Hancock
Keyword(s):  
Analysis Of Variance ◽  
Infinite Number ◽  
Critical Values ◽  
Multiple Comparison ◽  
Treatment Groups ◽  
Small Set ◽  
F Distribution ◽  
Multiple Comparison Procedure ◽  
Post Hoc

Scheffé’s test ( Scheffé, 1953 ), which is commonly used to conduct post hoc contrasts among k group means, is unnecessarily conservative because it guards against an infinite number of potential post hoc contrasts when only a small set would ever be of interest to a researcher. This paper identifies a set of post hoc contrasts based on subsets of the treatment groups and simulates critical values from the appropriate multivariate F-distribution to be used in place of those associated with Scheffé’s test. The proposed method and its critical values provide a uniformly more powerful post hoc procedure.

Study on the Interlaboratory Comparison Test of the Electronic Test Method for Raw Silk

2012 ◽  
Vol 241-244 ◽  
pp. 317-321
Author(s):  
Jian Mei Xu ◽  
Ying Zhou ◽  
Suo Zhuai Dong ◽  
Francesco Gatti ◽  
Dong Ping Wu ◽  
...  
Keyword(s):  
Analysis Of Variance ◽  
Optical Sensor ◽  
Interlaboratory Comparison ◽  
Test Method ◽  
Multiple Comparison ◽  
International Standard ◽  
Comparison Test ◽  
Testing Method ◽  
Multiple Comparison Procedure ◽  
The Difference

To establish an international standard on the electronic testing method for raw silk, the interlaboratory comparison tests of the electronic testing method for raw silk are done. Five lots of soaked silk are sampled and tested by four machines of the same type in four labs, 13 items including the defects and evenness information of each lot of silk are measured. The analysis of variance and multiple comparison procedure are used to find whether there exist significant differences among the four machines; and the result shows that there are no significant differences among the machines in testing these items except for the item of IPMe by optical sensor. The reason for the difference is analyzed, and the measure for dismissing the difference is proposed.

scholarly journals Effect of phoneme variations on blind reverberation time estimation

Acta Acustica ◽  
2020 ◽  
Vol 4 (1) ◽  
pp. 3
Author(s):  
Andrea Andrijašević
Keyword(s):  
Time Estimation ◽  
Multiple Comparison ◽  
Reverberation Time ◽  
Impulse Responses ◽  
Estimation Errors ◽  
Significance Level ◽  
Frequency Bands ◽  
Interaction Terms ◽  
Multiple Comparison Procedure

This study focuses on an unexplored aspect of the performance of algorithms for blind reverberation time (T) estimation – on the effect that speech signal’s phonetic content has on the value of the estimate of T that is obtained from the reverberant version of that signal. To this end, the performance of three algorithms is assessed on a set of logatome recordings artificially reverberated with room impulse responses from four rooms, with their T20 value in the [0.18, 0.55] s interval. Analyses of variance showed that the null hypotheses of equal means of estimation errors can be rejected at the significance level of 0.05 for the interaction terms between the factors “vowel”, “consonant”, and “room”, while the results of Tukey’s multiple comparison procedure revealed that there are both some similarities in the behaviour of the algorithms and some differences, where the latter are stemming from the differences in the details of algorithms’ implementation such as the number of frequency bands and whether T is estimated continuously or only on the selected, the so-called speech decay, segments of the signal.

Assessment of variance & distribution in data for effective use of statistical methods for product quality prediction

2018 ◽  
Vol 66 (4) ◽  
pp. 344-355 ◽  
Author(s):  
Iris Weiß ◽  
Birgit Vogel-Heuser
Keyword(s):  
Data Mining ◽  
Product Quality ◽  
Statistical Methods ◽  
Analysis Of Variance ◽  
Production System ◽  
Production Systems ◽  
High Potential ◽  
Quality Prediction ◽  
Automated Production ◽  
Effective Use

AbstractData mining in automated production systems provide high potential to increase the Overall Equipment Effectiveness. Nevertheless, data of such machines/plants include specific characteristics regarding the variance and distribution of the dataset. For modelling product quality prediction, these characteristics have to be analysed to interpret the results correctly. Therefore, an approach for the analysis of variance and distribution of datasets is proposed. The evaluation of this approach validates the developed guidelines, which identify the reasons for inconsistent prediction results based on two different datasets of the same production system.

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