2. In a clinical study, the mouths of 60 patients with mild or moderate oral ulcers were pasted with a particular type of oral membrane. The membrane was gently pressed for several seconds, and was used after cleaning the oral cavity four times a day (after breakfast, lunch, dinner, and before going to bed). One piece was pasted onto each ulcer for 5 days. Taking the ulcer area as the main evaluation indicator, after 5 days of treatment, it was found that the ulcer area was significantly reduced, and this effect was statistically significant. Therefore, it was concluded that the oral membrane had a positive curative effect in the treatment of oral ulcers.

(a) Do you agree with the conclusion of this research? If not, please give your reasons and state how to improve the research?

(b) Could the research be randomized? What is the purpose of randomization in this case?

(c) Is there a control group in this research? Which kind of control discussed in this chapter could be adopted here? Please explain their advantages and downsides in the context of current research.

(d) Is the blindness principle appropriate in this research? Can a single-blind or double-blind approach be used? Can a third-party evaluation be used?

Please give the reasons for your answer.

(e) How is the replication principle manifested in this research?