Conditional proportions by stratum
The ten strata represent performance levels based on the corrected score X(−i).
Hover over a point to see its values.
Focal = Female
Reference = Male
Calculation by stratum
Each conditional difference is Δk = pFk − pRk.
Weight wk is the proportion of the focal group in stratum k.
| Stratum | NFk | NRk | pFk | pRk | Δk | wk | Ck |
|---|
Formulas and terms
STD P-DIF is built in four steps: stratum weight, conditional difference,
stratum contribution and the sum of the contributions.
wk =
NFkNF
Δk = pFk − pRk
Ck = wk × Δk
STD P-DIF =
ΣKk=1
Ck
k: performance stratum.
K: total number of strata.
NFk: number of people in the focal group in stratum k.
NF: total number of people in the focal group.
pFk: proportion correct for the focal group in stratum k.
pRk: proportion correct for the reference group in stratum k.
wk: weight for stratum k based on the focal-group distribution.
Δk: difference between focal and reference proportions correct in stratum k.
Ck: contribution of stratum k to STD P-DIF.