A survey shows that 15% of nurses are being underpaid

A survey shows that 15% of nurses are being underpaid in a hospital that employs 200 nurses. 

(i) Construct a 90% confidence interval to represent the proportion of underpaid nurses in the hospital. Give an interpretation of this interval. 

(ii) Suppose that in another hospital, 12% of the 120 nurses employed are underpaid. Construct a 90% confidence interval for the difference in proportions of nurses being underpaid at both hospitals.