generator function used to generate random numbers.
nCont
gives the number of contaminated observations. Values between 0
and 1 will be treated as probability. If type is 'unit' and length is
larger than 1, the expected length is the number of areas. If type is
'area' and length is larger than 1 the values are interpreted as area
positions; i.e. c(1, 3) is interpreted as the first and 3rd area in
the data is contaminated.
type
"unit" or "area" - unit- or area-level contamination.
areaVar
character with variable name(s) identifying areas.
fixed
TRUE fixes the observations which will be contaminated. FALSE
will result in a random selection of observations or areas.