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Least-squares fitting with errors in the response and predictor

Published online by Cambridge University Press:  14 November 2012

T. Burr*
Affiliation:
Statistical Sciences, Los Alamos National Laboratory, USA
S. Croft
Affiliation:
Safeguards Science and Technology, Los Alamos National Laboratory, USA
B.C. Reed
Affiliation:
Department of Physics, Alma College, USA
*
Correspondence: tburr@lanl.gov
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Abstract

Least squares regression is commonly used in metrology for calibration and estimation. In regression relating a response y to a predictor x, the predictor x is often measured with error that is ignored in analysis. Practitioners wondering how to proceed when x has non-negligible error face a daunting literature, with a wide range of notation, assumptions, and approaches. For the model ytrue = β0 + β1   xtrue, we provide simple expressions for errors in predictors (EIP) estimators \hbox{$\Hat{{\beta }}_{0, {\rm EIP}} $}β̂0, EIP for β0 and \hbox{$\Hat{{\beta }}_{1, {\rm EIP}} $}β̂1, EIP for β1 and for an approximation to covariance (\hbox{$\Hat{{\beta }}_{0, {\rm EIP}} $}β̂0, EIP, \hbox{$\Hat{{\beta }}_{1, {\rm EIP}} $}β̂1, EIP). It is assumed that there are measured data x = xtrue + ex, and y = ytrue + ey with errors ex in x and ey in y and the variances of the errors ex and ey are allowed to depend on xtrue and ytrue, respectively. This paper also investigates the accuracy of the estimated cov(\hbox{$\Hat{{\beta }}_{0, {\rm EIP}} $}β̂0, EIP, \hbox{$\Hat{{\beta }}_{1, {\rm EIP}} $}β̂1, EIP) and provides a numerical Bayesian alternative using Markov Chain Monte Carlo, which is recommended particularly for small sample sizes where the approximate expression is shown to have lower accuracy than desired.

Type
Research Article
Copyright
© EDP Sciences 2012

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References

R. Carroll, D. Ruppert, L. Stefanski, C. Crainiceanu, Measurement Error in Nonlinear Models (Chapman & Hall, 2006)
W. Deming, Statistical Adjustment of Data (Wiley, 1943)
W. Fuller, Measurement Error Models (Wiley, 1987)
Reed, B., A spreadsheet for linear least-squares fitting with errors in both coordinates, Phys. Educ. 45, 9395 (2010) CrossRefGoogle Scholar
Reed, B., Linear least-squares fits with errors in both coordinates. II : Comments on parameter variances, Am. J. Phys. 60, 5962 (1992) CrossRefGoogle Scholar
York, D., Evensen, N., Martinez, M., Delgado, J., Unified equations for the slope, intercept, and standard errors of the best straight line, Am. J. Phys. 72, 367375 (2004) CrossRefGoogle Scholar
Wang, C., Iyer, H., Fiducial approach for assessing agreement between two instruments, Metrologia 45, 415421 (2008) CrossRefGoogle Scholar
Brown, M., Robust line estimation with errors in both variables, J. Am. Stat. Assoc. 77, 7179 (1982) CrossRefGoogle Scholar
Madansky, A., The fitting of straight lines when both variables are subject to errors, J. Am. Stat. Assoc. 54, 173205 (1959) CrossRefGoogle Scholar
W. Press, S. Teukolsky, W. Vettterling, B. Flannery, Numerical Recipes, The Art of Scientific Computing, 3rd edn. (Cambridge University Press, 2007)
Toivanen, J., Dobaczewski, J., Kortelainen, M., Mizuyama, K., Error analysis of nuclear mass fits, Phys. Rev. C 78, 03430610343068 (2008) CrossRefGoogle Scholar
R Development Core Team 2004 R : A Language and Environment for Statistical Computing
Burr, T., Knepper, P., A study of the effect of measurement error in predictor variables in nondestructive assay, Appl. Radiat. Isotopes 53, 547555 (2000) CrossRefGoogle ScholarPubMed
Elster, C., Toman, B., Bayesian uncertainty analysis for a regression model versus application of GUM supplement 1 to the least-squares estimate, Metrologia 48, 233240 (2011) CrossRefGoogle Scholar
W. Gilks, S. Richardson, D. Spiegelhalter, Markov Chain Monte Carlo in Practice (Chapman & Hall/CRC, 1996)
Dellaportas, P., Stephens, D., Bayesian analysis of errors-in-variables regression models, Biometrics 51, 10851095 (1995) CrossRefGoogle Scholar
Kulathinal, S., Kuulasmaa, K., Gasbarra, D., Estimation of an errors-in-variables regression model with the variance of the measurement errors vary between the observations, Stat. Med. 21, 10891101 (2002) CrossRefGoogle ScholarPubMed
M. DeGroot, Probability and Statistics, 2nd edn. (Addison-Wesley, 1986)