Question: According to a June 2009 report (http://www.alertnet.org/thenews/newsdesk/L31011082.htm), 68% of people with "green" jobs in North America felt that they had job security, whereas 60% of people with green jobs in the United Kingdom felt that they had job security. Suppose that these results were based on samples of 305 people with green jobs from North America and 280 people with green jobs from the United Kingdom.

a. Construct a 96% confidence interval for the difference between the two population proportions.

b. Using the 2% significance level, can you conclude that the proportion of all people with green jobs in North America who feel that they have job security is higher than the corresponding proportion for the United Kingdom? Use the critical-value approach.

c. Repeat part b using the p-value approach.