- x
A data frame or a mixed model object.
- select
Character vector (or formula) with names of variables to select
that should be checked. If x is a mixed model object, this argument
will be ignored.
- by
Character vector (or formula) with the name of the variable that
indicates the group- or cluster-ID. For cross-classified or nested designs,
by can also identify two or more variables as group- or cluster-IDs. If
the data is nested and should be treated as such, set nested = TRUE. Else,
if by defines two or more variables and nested = FALSE, a cross-classified
design is assumed. If x is a model object, this argument will be ignored.
For nested designs, by can be:
a character vector with the name of the variable that indicates the
levels, ordered from highest level to lowest (e.g.
by = c("L4", "L3", "L2").
a character vector with variable names in the format by = "L4/L3/L2",
where the levels are separated by /.
See also section De-meaning for cross-classified designs and
De-meaning for nested designs below.
- nested
Logical, if TRUE, the data is treated as nested. If FALSE,
the data is treated as cross-classified. Only applies if by contains more
than one variable.
- group
Deprecated. Use by instead.