Answer:
Thus difference in sample proportions would be the unbiased estimate of the difference between the two proportions
Step-by-step explanation:
Given that you construct a confidence interval for the difference between two proportions
Let the proportions be p1 and p2
Sample sizes be n1 and n2
For samples of larger size randomly drawn we know that
p1 follows Normal with mean = sample proportion = p1 and
p2 is N with mean = sample proportion p2
Assuming these two proportions are independent we have
p1-p2 will follow a normal distribution with mean = p1-p2
Thus difference in sample proportions would be the unbiased estimate of the difference between the two proportions