Discuss the sample (size, sampling method, and setting) and critique the sampling methods (appropriateness of sampling e.g. inclusion/exclusion criteria; representativeness of sample to population; comparability of groups [if groups present]). Use words found in your textbook that help you such as random/nonrandom, probability/nonprobability, convenience, purposive, etc. Do you see any potential bias in the sample? Remember that bias results in a distortion in the results of a study.
Ngowe, M., Eyenga, V., Kengn, B., Bahebeck, J. & Sosso, A. (2010). Chewing gum reduces
postoperative ileus after open appendectomy. Acta Chir Belg, 110(2), 195-199.