Where
is the proportion in the total sample and
is the proportion in the sub-group,
and
are their respective effective sample sizes, and
is the proportion of the total population in sub-group
:
,
where:
,
,
,
,
, or, if Weights and significance is set to Un-weighted sample size in tests (see Weights, Effective Sample Size and Design Effects), 
is 1 if Bessel's correction is selected for Proportions in Statistical Assumptions and 0 otherwise,
is Extra Deff, and
is the proportion of the Population represents by the sub-group.