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Construction of age‐related reference centiles using absolute residuals
Author(s) -
Altman Douglas G.
Publication year - 1993
Publication title -
statistics in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.996
H-Index - 183
eISSN - 1097-0258
pISSN - 0277-6715
DOI - 10.1002/sim.4780121003
Subject(s) - standard deviation , mathematics , statistics , parametric statistics , simple (philosophy) , standard error , reference values , normal distribution , function (biology) , medicine , philosophy , epistemology , evolutionary biology , biology
This paper proposes a simple approach to the parametric derivation of age‐related reference ranges which avoids the creation of arbitrary age groups, copes easily with a non‐linear relation between variability and age, and is computationally simple. After the mean is modelled as a function of age, the age‐specific standard deviation is estimated by regressing the absolute residuals on age. The method assumes that the data are, or can be transformed to be, normal at each age, and uses the properties of the half normal distribution. An example is given using 450 measurements of fetal foot length.