Estimation of difference among population proportions
Assume the two proportions be described by P1 and P2, respectively,Then the difference absolute between the two proportions is described by (P_{1} - P_{2})
The standard error is described by:-
S_{(P1 - P2)} = √{(pq/n_{1}) + (pq/n_{2})} = where p = (p_{1}n_{1} + p_{2}n_{2})/(n_{1} + n_{1}) and q = 1 - p
Then described the confidence level, the confidence interval among the two population proportions is described by
(P1 - P2) ± Confidence level S_{(P1 - P2)}
= (P1 - P2) ± Z √{(pq/n_{1}) + (pq/n_{2})}
Whereas P = (p_{1}n_{1} + p_{2}n_{2})/(n_{1} + n_{1}) always remember to convert P_{1} and P_{2} to P.