Forty-two cruise ships come to Alaska's Glacier Bay every year. The state tourist board wants to estimate the average cruise passenger's satisfaction from this experience, rated on a scale of 0 to 100. Since the ships' arrivals are evenly spread throughout the season, simple random sampling is costly and time-consuming. Therefore, the agency decides to send its volunteers to board the first five ships of the season, consider them as clusters, and randomly choose 50 passengers in each ship for interviewing.

a. Is the method employed single-stage cluster sampling? Explain.

b. Is the method employed two-stage cluster sampling? Explain.

c. Suppose that each of the ships has exactly 50 passengers. Is the proposed method single-stage cluster sampling?

d. The 42 ships belong to 12 cruise ship companies. Each company has its own characteristics in terms of price, luxury, services, and type of passengers. Suggest an alternative sampling method, and explain its benefits.