predictNormBC {cNORM} | R Documentation |
In addition to the numeric solution of the inversion of the regression function applied in 'predictNorm', this function can be used retrieving the norm scores at a specific age via the parametric box cox power transformation. Please provide the box cox parameters retrieved via the 'boxcox'-function and a raw value.
predictNormBC(boxcoxParameters, raw, scale = "percentile")
boxcoxParameters |
The parameters of the box cox power function, calculated via 'boxcox' |
raw |
The raw value (>0) |
scale |
type of norm scale, either T, IQ, z or percentile (= no transformation; default); a double vector with the mean and standard deviation can as well, be provided f. e. c(10, 3) for Wechsler scale index points |
the predicted raw value
Cole, T. J., & Green, P. J. (1992). Smoothing reference centile curves: the LMS method and penalized likelihood. Statistics in medicine, 11(10), 1305-1319.
Box, G. E., & Cox, D. R. (1964). An analysis of transformations. Journal of the Royal Statistical Society. Series B (Methodological), 211-252.
boxcox, predictNorm, predictRawBC
# model sample data set model <- bestModel(prepareData()) # fitting scores of regression model box cox power function at specific age and retrieving # the parameters for the box cox power function bcParameters <- boxcox(model, 3) # predict norm value for raw value 15 at age 3 based on the regression model and via box cox predictNormBC(bcParameters, 15, scale="T") predictNorm(15, 3, model, minNorm=25, maxNorm=75)