This function will only add an overall column at the top level of splitting, NOT within existing column splits.
See add_overall_level() for the recommended way to add overall columns more generally within existing splits.
Value
A PreDataTableLayouts object suitable for passing to further layouting functions, and to build_table().
Examples
lyt <- basic_table() %>%
  split_cols_by("ARM") %>%
  add_overall_col("All Patients") %>%
  analyze("AGE")
lyt
#> A Pre-data Table Layout
#> 
#> Column-Split Structure:
#> ARM (lvls) 
#>  (all obs) 
#> 
#> Row-Split Structure:
#> AGE (** analysis **) 
#> 
tbl <- build_table(lyt, DM)
tbl
#>        A: Drug X   B: Placebo   C: Combination   All Patients
#> —————————————————————————————————————————————————————————————
#> Mean     34.91       33.02          34.57           34.22