Question

Use the normal distribution to find a confidence interval for a difference in proportions p1-p2 given the relevant sample results. Assume the results come from random samples.

A 99% confidence interval for p1-p2 given that p-hat = 0.25 with n1=40 and p2-hat = 0.35 with n2=100. Give the best estimate for p1-p2 , the margin of error and the confidence interval. Round your answer for the best estimate to two decimal places and round your answers for the margin of error and the confidence interval to three decimal places.

Best Estimate:

Margin of Error:

Confidence Interval:

Answer 1

The statistical software output for this problem is:

Hence,

Best estimate = -0.1

Margin of error = (0.11493 + 0.31493)/2 = 0.215

Confidence interval: (-0.315, 0.115)