3. In a clinical trial for the treatment of angina pectoris, 172 patients were randomly divided into two groups and were given either sustained-release tablets or ordinary tablets. The results are given in Table 12.10. The aim is to investigate whether there is any difference between the two groups in terms of treatment effectiveness.

Please answer the following questions:

(a) To test the hypothesis, is it appropriate to conduct a 2 test here? Explain the reason. What is your choice?

(b) State H0 and H1 .

(c) Choose a method discussed in this chapter to test the difference.

(d) Because there are many ties in this case, how should you deal with the ties?
What could happen if the ties are not taken into account in the calculation process?