A non-parametric conditional bivariate reference region with an application to height/weight measurements on normal girls.
A conceptually simple two-dimensional conditional reference curve is described. The curve gives a decision basis for determining whether a bivariate response from an individual is "normal" or "abnormal" when taking into account that a third (conditioning) variable may influence the bivariate response. The reference curve is not only characterized analytically but also by geometric properties that are easily communicated to medical doctors - the users of such curves. The reference curve estimator is completely non-parametric, so no distributional assumptions are needed about the two-dimensional response. An example that will serve to motivate and illustrate the reference is the study of the height/weight distribution of 7-8-year-old Danish school girls born in 1930, 1950, or 1970.
Petersen
Jorgen Holm
JH
Department of Biostatistics, University of Copenhagen, DK-1014 Copenhagen K, Denmark. J.H.Petersen@biostat.ku.dk
D000293:Adolescent; D000465:Algorithms; D000886:Anthropometry / Q000379:methods*; D001699:Biometry / Q000379:methods*; D001827:Body Height; D001835:Body Weight; D003627:Data Interpretation, Statistical; D015987:Effect Modifier, Epidemiologic; D005260:Female; D006801:Humans; D012016:Reference Values