Final answer:
To construct a confidence interval for the difference between two proportions, you use an unbiased estimate of the difference between the two proportions.
Step-by-step explanation:
When constructing a confidence interval for the difference between two proportions, an unbiased estimate of the difference between the two proportions is obtained using the formula:
(p1 - p2) ± ME
Where:
- p1 and p2 are the sample proportions
- ME is the margin of error
The margin of error is calculated as:
ME = z * sqrt((p1*(1-p1)/n1) + (p2*(1-p2)/n2))
Where:
- z is the z-score corresponding to the desired confidence level
- n1 and n2 are the sample sizes
Using this formula, you can calculate the confidence interval for the difference between two proportions.