A Variation of the FTest for Determining Statistical Relevance of Particular Parameters in EXAFS Fits
Abstract
A general problem when fitting EXAFS data is determining whether particular parameters are statistically significant. The Ftest is an excellent way of determining relevancy in EXAFS because it only relies on the ratio of the fit residual of two possible models, and therefore the data errors approximately cancel. Although this test is widely used in crystallography (there, it is often called a ''Hamilton test'') and has been properly applied to EXAFS data in the past, it is very rarely applied in EXAFS analysis. We have implemented a variation of the Ftest adapted for EXAFS data analysis in the RSXAP analysis package, and demonstrate its applicability with a few examples, including determining whether a particular scattering shell is warranted, and differentiating between two possible species or two possible structures in a given shell.
 Authors:
 Physics Department, University of California, Santa Cruz, California 95060 (United States)
 (United States)
 Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)
 Publication Date:
 OSTI Identifier:
 21054572
 Resource Type:
 Journal Article
 Resource Relation:
 Journal Name: AIP Conference Proceedings; Journal Volume: 882; Journal Issue: 1; Conference: XAFS13: 13. international conference on Xray absorption fine structure, Stanford, CA (United States), 914 Jul 2006; Other Information: DOI: 10.1063/1.2644450; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
 Country of Publication:
 United States
 Language:
 English
 Subject:
 36 MATERIALS SCIENCE; ABSORPTION SPECTROSCOPY; CRYSTAL STRUCTURE; CRYSTALLOGRAPHY; DATA ANALYSIS; ERRORS; FINE STRUCTURE; SCATTERING; TESTING; VARIATIONS; XRAY SPECTROSCOPY
Citation Formats
Downward, L., Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, Booth, C. H., Lukens, W. W., and Bridges, F.. A Variation of the FTest for Determining Statistical Relevance of Particular Parameters in EXAFS Fits. United States: N. p., 2007.
Web. doi:10.1063/1.2644450.
Downward, L., Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, Booth, C. H., Lukens, W. W., & Bridges, F.. A Variation of the FTest for Determining Statistical Relevance of Particular Parameters in EXAFS Fits. United States. doi:10.1063/1.2644450.
Downward, L., Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, Booth, C. H., Lukens, W. W., and Bridges, F.. Fri .
"A Variation of the FTest for Determining Statistical Relevance of Particular Parameters in EXAFS Fits". United States.
doi:10.1063/1.2644450.
@article{osti_21054572,
title = {A Variation of the FTest for Determining Statistical Relevance of Particular Parameters in EXAFS Fits},
author = {Downward, L. and Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 and Booth, C. H. and Lukens, W. W. and Bridges, F.},
abstractNote = {A general problem when fitting EXAFS data is determining whether particular parameters are statistically significant. The Ftest is an excellent way of determining relevancy in EXAFS because it only relies on the ratio of the fit residual of two possible models, and therefore the data errors approximately cancel. Although this test is widely used in crystallography (there, it is often called a ''Hamilton test'') and has been properly applied to EXAFS data in the past, it is very rarely applied in EXAFS analysis. We have implemented a variation of the Ftest adapted for EXAFS data analysis in the RSXAP analysis package, and demonstrate its applicability with a few examples, including determining whether a particular scattering shell is warranted, and differentiating between two possible species or two possible structures in a given shell.},
doi = {10.1063/1.2644450},
journal = {AIP Conference Proceedings},
number = 1,
volume = 882,
place = {United States},
year = {Fri Feb 02 00:00:00 EST 2007},
month = {Fri Feb 02 00:00:00 EST 2007}
}

A general problem when fitting EXAFS data is determining whether particular parameters are statistically significant. The Ftest is an excellent way of determining relevance in EXAFS because it only relies on the ratio of the fit residual of two possible models, and therefore the data errors approximately cancel. Although this test is widely used in crystallography (there, it is often called a 'Hamilton test') and has been properly applied to EXAFS data in the past, it is very rarely applied in EXAFS analysis. We have implemented a variation of the Ftest adapted for EXAFS data analysis in the RSXAP analysismore »

A Variation of the FTest for Determining Statistical Relevance ofParticular Parameters in EXAFS Fits
A general problem when fitting EXAFS data is determining whether particular parameters are statistically significant. The Ftest is an excellent way of determining relevancy in EXAFS because it only relies on the ratio of the fit residual of two possible models, and therefore the data errors approximately cancel. Although this test is widely used in crystallography (there, it is often called a 'Hamilton test') and has been properly applied to EXAFS data in the past, it is very rarely applied in EXAFS analysis. We have implemented a variation of the Ftest adapted for EXAFS data analysis in the RSXAP analysismore » 
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