calc.zcent: Calculate the Standardized Values of a Variable for Each...

In wviechtb/esmpack: Functions that Facilitate Preparation and Management of ESM/EMA Data

Calculate the Standardized Values of a Variable for Each Subject

Description

Function that calculates the standardized values of a particular variable for each subject.

Usage

calc.zcent(x, id, data, na.rm=TRUE)

Arguments

x	argument to specify the variable.
id	argument to specify a subject id variable.
data	optional data frame that contains the variables specified above.
na.rm	logical indicating whether missing values should be removed before computing the means and standard deviations for computing the standardized values (default is TRUE).

Details

The function computes the standardized values of a particular variable for each subject. Note that the values are standardized within subjects (i.e., based on the subject-level means and standard deviations), so this is analogous to ‘within-person mean centering’, except that the centered values are also divided by the person-level standard deviations.

Value

A vector.

Author(s)

Wolfgang Viechtbauer [e-mail]

See Also

calc.mcent

Examples

# illustrative dataset
dat <- data.frame(subj=rep(1:4, each=5),
                  obs = 1:5,
                  age = rep(c(20,31,27,22), each=5),
                  stress = c(2,3,NA,4,2, 3,3,NA,3,NA, 1,1,2,6,4, 1,2,1,3,1))
dat

# calculate the standardized values of the stress variable
dat$cstress <- calc.zcent(stress, subj, data=dat)
dat

wviechtb/esmpack documentation built on April 12, 2025, 9:48 p.m.