Robust Correlation Measures

Robust Correlation Measures PDF Author: Chris Tofallis
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Book Description
It is well established that the standard measure of correlation (Pearson's product-moment) is very sensitive to outliers. It can give extremely misleading results when a few or even a single outlier is present. A number of robust correlation measures have been proposed. We do not consider estimators which require trimming (discarding) of some arbitrary fraction of the data, nor those which require iterative computation. Our overall aim is to find a practical and simple robust measure of correlation which can be recommended to practitioners alongside the classic Pearson and Spearman measures. The well known data sets of Anscombe are used to provide an initial assessment of these estimators. These four data sets were designed to have identical Pearson correlation coefficients as well as identical regression lines and other regression statistics. Nevertheless, visual inspection of their scatter-graphs indicates very different patterns. For data set C, there is a perfect linear relationship for all but one of the data points; whereas for data set D, apart from one outlier, all points have the same x-value and so there is essentially no co-variation or interdependence between the variables. We prefer a robust correlation measure to have a near-zero value for set D, and a high value for set C, with the other two data sets giving an intermediate value.

Robust Correlation Measures

Robust Correlation Measures PDF Author: Chris Tofallis
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Book Description
It is well established that the standard measure of correlation (Pearson's product-moment) is very sensitive to outliers. It can give extremely misleading results when a few or even a single outlier is present. A number of robust correlation measures have been proposed. We do not consider estimators which require trimming (discarding) of some arbitrary fraction of the data, nor those which require iterative computation. Our overall aim is to find a practical and simple robust measure of correlation which can be recommended to practitioners alongside the classic Pearson and Spearman measures. The well known data sets of Anscombe are used to provide an initial assessment of these estimators. These four data sets were designed to have identical Pearson correlation coefficients as well as identical regression lines and other regression statistics. Nevertheless, visual inspection of their scatter-graphs indicates very different patterns. For data set C, there is a perfect linear relationship for all but one of the data points; whereas for data set D, apart from one outlier, all points have the same x-value and so there is essentially no co-variation or interdependence between the variables. We prefer a robust correlation measure to have a near-zero value for set D, and a high value for set C, with the other two data sets giving an intermediate value.

Robust Correlation

Robust Correlation PDF Author: Georgy L. Shevlyakov
Publisher: John Wiley & Sons
ISBN: 1119264537
Category : Mathematics
Languages : en
Pages : 352

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Book Description
This bookpresents material on both the analysis of the classical concepts of correlation and on the development of their robust versions, as well as discussing the related concepts of correlation matrices, partial correlation, canonical correlation, rank correlations, with the corresponding robust and non-robust estimation procedures. Every chapter contains a set of examples with simulated and real-life data. Key features: Makes modern and robust correlation methods readily available and understandable to practitioners, specialists, and consultants working in various fields. Focuses on implementation of methodology and application of robust correlation with R. Introduces the main approaches in robust statistics, such as Huber’s minimax approach and Hampel’s approach based on influence functions. Explores various robust estimates of the correlation coefficient including the minimax variance and bias estimates as well as the most B- and V-robust estimates. Contains applications of robust correlation methods to exploratory data analysis, multivariate statistics, statistics of time series, and to real-life data. Includes an accompanying website featuring computer code and datasets Features exercises and examples throughout the text using both small and large data sets. Theoretical and applied statisticians, specialists in multivariate statistics, robust statistics, robust time series analysis, data analysis and signal processing will benefit from this book. Practitioners who use correlation based methods in their work as well as postgraduate students in statistics will also find this book useful.

Robust Correlation

Robust Correlation PDF Author: Georgy L. Shevlyakov
Publisher: John Wiley & Sons
ISBN: 1118493451
Category : Mathematics
Languages : en
Pages : 353

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Book Description
This bookpresents material on both the analysis of the classical concepts of correlation and on the development of their robust versions, as well as discussing the related concepts of correlation matrices, partial correlation, canonical correlation, rank correlations, with the corresponding robust and non-robust estimation procedures. Every chapter contains a set of examples with simulated and real-life data. Key features: Makes modern and robust correlation methods readily available and understandable to practitioners, specialists, and consultants working in various fields. Focuses on implementation of methodology and application of robust correlation with R. Introduces the main approaches in robust statistics, such as Huber’s minimax approach and Hampel’s approach based on influence functions. Explores various robust estimates of the correlation coefficient including the minimax variance and bias estimates as well as the most B- and V-robust estimates. Contains applications of robust correlation methods to exploratory data analysis, multivariate statistics, statistics of time series, and to real-life data. Includes an accompanying website featuring computer code and datasets Features exercises and examples throughout the text using both small and large data sets. Theoretical and applied statisticians, specialists in multivariate statistics, robust statistics, robust time series analysis, data analysis and signal processing will benefit from this book. Practitioners who use correlation based methods in their work as well as postgraduate students in statistics will also find this book useful.

Bootstrapping Robust Measures of Correlation

Bootstrapping Robust Measures of Correlation PDF Author: Jason Eric King
Publisher:
ISBN:
Category :
Languages : en
Pages : 610

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Book Description


Introduction to Robust Estimation and Hypothesis Testing

Introduction to Robust Estimation and Hypothesis Testing PDF Author: Rand R. Wilcox
Publisher: Academic Press
ISBN: 0123869838
Category : Mathematics
Languages : en
Pages : 713

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Book Description
"This book focuses on the practical aspects of modern and robust statistical methods. The increased accuracy and power of modern methods, versus conventional approaches to the analysis of variance (ANOVA) and regression, is remarkable. Through a combination of theoretical developments, improved and more flexible statistical methods, and the power of the computer, it is now possible to address problems with standard methods that seemed insurmountable only a few years ago"--

Robustness in Data Analysis

Robustness in Data Analysis PDF Author: Georgy L. Shevlyakov
Publisher: Walter de Gruyter
ISBN: 3110936003
Category : Mathematics
Languages : en
Pages : 325

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Book Description
The series is devoted to the publication of high-level monographs and surveys which cover the whole spectrum of probability and statistics. The books of the series are addressed to both experts and advanced students.

The Gerber Statistic

The Gerber Statistic PDF Author: Sander Gerber
Publisher:
ISBN:
Category :
Languages : en
Pages : 7

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Book Description
We introduce the Gerber statistic, a robust measure of correlation. The statistic extends Kendall's Tau by counting the proportion of simultaneous co-movements in series when their amplitudes exceed data-dependent thresholds. This is unlike the standard Pearson correlation that is sensitive to outliers or the Spearman correlation that relies on ranking observations. Since the statistic is neither affected by extremely large or extremely small movements, it is especially suited to financial time series since these can exhibit extreme movements as well as a great amount of noise. Therefore, the statistic can advantageously be converted into a robust estimate of a covariance matrix that is suitable for portfolio optimization.

A Practical, Powerful, Robust and Interpretable Family of Correlation Coefficients

A Practical, Powerful, Robust and Interpretable Family of Correlation Coefficients PDF Author: Savas Papadopoulos
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Book Description
If we conducted a competition for which statistical quantity would be the most valuable in exploratory data analysis, the winner would most likely be the correlation coefficient with a significant difference from its first competitor. In addition, most data applications contain non-normal data with outliers without being able to be converted to normal data. Therefore, we search for robust correlation coefficients to nonnormality and outliers that could be applied to all applications and detect influenced or hidden correlations not recognized by the most popular correlation coefficients. We introduce a correlation-coefficient family with the Pearson and Spearman coefficients as specific cases. Other family members provide desirable lower p-values than those derived by the standard coefficients in the earlier problems. The proposed family of coefficients, their cut-off points, and p-values, computed by permutation tests, could be applied by all scientists analyzing data. We share simulations, code, and real data by email or the internet.

Comprehensive Chemometrics

Comprehensive Chemometrics PDF Author: Steven Brown
Publisher: Elsevier
ISBN: 0444641661
Category : Science
Languages : en
Pages : 2948

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Book Description
Comprehensive Chemometrics, Second Edition, Four Volume Set features expanded and updated coverage, along with new content that covers advances in the field since the previous edition published in 2009. Subject of note include updates in the fields of multidimensional and megavariate data analysis, omics data analysis, big chemical and biochemical data analysis, data fusion and sparse methods. The book follows a similar structure to the previous edition, using the same section titles to frame articles. Many chapters from the previous edition are updated, but there are also many new chapters on the latest developments. Presents integrated reviews of each chemical and biological method, examining their merits and limitations through practical examples and extensive visuals Bridges a gap in knowledge, covering developments in the field since the first edition published in 2009 Meticulously organized, with articles split into 4 sections and 12 sub-sections on key topics to allow students, researchers and professionals to find relevant information quickly and easily Written by academics and practitioners from various fields and regions to ensure that the knowledge within is easily understood and applicable to a large audience Presents integrated reviews of each chemical and biological method, examining their merits and limitations through practical examples and extensive visuals Bridges a gap in knowledge, covering developments in the field since the first edition published in 2009 Meticulously organized, with articles split into 4 sections and 12 sub-sections on key topics to allow students, researchers and professionals to find relevant information quickly and easily Written by academics and practitioners from various fields and regions to ensure that the knowledge within is easily understood and applicable to a large audience

Robust Measures of Association

Robust Measures of Association PDF Author: Amy Poon Davis
Publisher:
ISBN:
Category :
Languages : en
Pages : 162

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Book Description