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-deming-'s input parameters -cv1()- and -cv2()- correspond to the coefficients of variations of the first and second methods (variables var1 and var2, respectively). These parameters reflect the precision of measurements for each of the two methods relative to the mean values. The coefficients of variations are used to compute the error variance ratio "lambda" as follows: lambda = cv2*mean(var2)/cv1*mean(var1). Note that in -deming-'s output the estimate of "lambda" is labeled as the "Variance ratio". Alternatively, the precision of measurements may be obtained from the duplicate measurements (if available) by computing the standard error of the difference between the duplicates for each method. The variance ratio is then computed as a ratio of these standard errors. This alternative specification, however, is not available with -deming-. In the absence of repeated measurements, Subramanian should obtain the values of the coefficients of variations for the two methods based on previous experience and the nature of the considered methods. By default, -deming- assumes coefficients of variations of 20% for each method. * * For searches and help try: * http://www.stata.com/support/faqs/res/findit.html * http://www.stata.com/support/statalist/faq * http://www.ats.ucla.edu/stat/stata/

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