calc.fun: Calculate some Summary Statistic of a Variable for Each...

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

Calculate some Summary Statistic of a Variable for Each Subject

Description

Function that calculates the summary statistic for a particular variable for each subject.

Usage

calc.fun(x, id, data, FUN, expand=FALSE, ...)

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.
FUN	function that computes the summary statistic of interest.
expand	logical indicating whether to expand the returned vector so that it can be added back to the dataset as a new variable (default is FALSE).
...	other arguments passed on to the function specified via FUN.

Details

The function computes the summary of a particular variable for each subject.

When expand=TRUE, the value of the statistic for each subject is repeated in such a way that the returned vector can be added back to the dataset as a new variable. See ‘Examples’.

Value

A vector.

Author(s)

Wolfgang Viechtbauer [e-mail]

See Also

calc.mean

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 subject-level SDs of the stress variable
calc.fun(stress, subj, data=dat, FUN=sd)

# remove the missings before computing the SDs
calc.fun(stress, subj, data=dat, FUN=sd, na.rm=TRUE)

# add this variable back to the original dataset
dat$sdstress <- calc.fun(stress, subj, data=dat, FUN=sd, na.rm=TRUE, expand=TRUE)
dat

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