The function get_xformed_variables() transforms the variables as
needed.
get_xformed_variables(
data,
response_vbl,
time_vbl,
xform = c("no", "no"),
shift = c(0, 0)
)The provided data frame with (a) new column(s) of the transformed variable(s).
A data frame with the columns specified by response_vbl,
time_vbl and batch_vbl.
A character string specifying the response variable name
that must be a column of data.
A character string specifying the time variable name that
must be a column of data.
A vector of two character strings specifying the transformation
of the response and the time variable. The default is “no”
transformation, i.e. c("no", "no"), where the first element
specifies the transformation of the \(x\) variable and the second
element the transformation of the \(y\) variable. Valid alternatives
for \(x\) and/or \(y\) variable transformation are "log"
(natural logarithm), "sqrt" (square root) and "sq" (square).
A vector of two values which will be added to the variables
\(x\) and/or \(y\) before they are transformed as specified by the
xform parameter, where the first element will be added to the
\(x\) variable and the second element to the \(y\) variable. The
purpose is to prevent an undefined state which could arise when variables
with values of \(\leq 0\) are log or square root transformed. The
default is c(0, 0).
The function get_xformed_variables() transforms the variables
(response_vbl and/or time_vbl) as specified by the parameters
xform and shift.