9 A study is conducted to determine whether there is a significant difference in union membership based on sex of the person. A random sample of 5000 factory-employed men were polled, and of this group, 785 were members of a union. A random sample of 3000 factory-employed women were also polled, and of this group, 327 were members of a union. Con- struct a 99% confidence interval on the difference in proportions P1 - P2