tbl. Data frame containing the columns to be summarized.
name
character. Name of the summary score column.
max_na
numeric, positive whole number. Number of missing items
allowed. NULL means no limit.
exclude
character vector. Values to be excluded from the summary score.
combine
logical. If TRUE (default), the summary score is
is appended as a new column to the input data frame. If FALSE, the
summary score is returned as a separate one-column data frame.