measurement error model - "simple" linear regression
Dear Troels, you might try McArdle, Limnol. Oceanogr., 48(3), 2003, 1363-1366 for some reading, and the pls package (newly updated) for tools. (I apologize if this information replicates previous postings, but Googling R-help McArdle 2005 draws a blank so I think I'm on safe ground!) Good luck! Andrew
On Sun, Oct 16, 2005 at 10:40:17PM +0200, Troels Ring wrote:
Dear friends, I found the thread on this subject this summer but wonder whether it has been taken any further. I have an important medical problem where X is computed from a three independent and complicated measurements (exchangeable sodium and potassium and total body water - i.e. X = (Nae+Ke)/TBW ) and Y is serum sodium concentration (all data in Edelman, JCI 1958). I have the individual data in the paper (but have not yet had time to enter it) and Edelman et al in fact reported measurement errors for most individual items. Edelman and coworkers made a linear regression of Y on X and now I would like to ascertain the importance of the fact that X was measured with error for the utility of the formula in clinical practice (since I believe it is being misused by ignoring this fact - and more). I found in Neter, Wasserman and Kutner 3. ed a general discussion of the problem - but would very much like a more recent presentation if available and application in R. Best wishes Troels Ring Aalborg, Denmark
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Andrew Robinson Senior Lecturer in Statistics Tel: +61-3-8344-9763 Department of Mathematics and Statistics Fax: +61-3-8344-4599 University of Melbourne, VIC 3010 Australia Email: a.robinson at ms.unimelb.edu.au Website: http://www.ms.unimelb.edu.au