predictNormBC {cNORM}R Documentation

Calculate the norm value for a given raw value based on the parametric box cox distribution

Description

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.

Usage

predictNormBC(boxcoxParameters, raw, scale = "percentile")

Arguments

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

Value

the predicted raw value

References

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.

See Also

boxcox, predictNorm, predictRawBC

Examples

# 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)

[Package cNORM version 1.2.0 Index]