1. A study aimed to investigate the relationship between chronic bronchitis and serum cholinesterase activity by comparing the serum cholinesterase activities of rats with chronic bronchitis and healthy rats. Sixteen Wistar rats were matched into eight pairs by litter, sex, and body weight. The rats in each pair were then randomly allocated to either the experimental or control group. The rats in the experimental group were supplied air containing 0.3 mg/m2 formaldehyde (chronic bronchitis rat model with inhalation of formaldehyde), and the control group was supplied clean air. The serum cholinesterase activity (μmol/ml) was measured after 8 weeks; the results are given in Table 8.4.

Please answer the following questions:

(a) What is the design of this study? What is the advantage of this design?

(b) Which method could be employed for testing the two population means in such a design? What are the necessary assumptions for applying the test?

(c) Is it appropriate to employ two independent samples t-test in this study? If not, what is the consequence of misusing a paired samples t-test with a two independent samples t-test?