Step 1 :Identify the null hypothesis and alternative hypothesis.
Step 2 :The null hypothesis is usually a statement of no effect or no difference. It is the hypothesis that the researcher is trying to disprove. In this case, the null hypothesis would be that the return rate is equal to 20%.
Step 3 :The alternative hypothesis is what you might believe to be true or hope to prove true. In this case, the alternative hypothesis is that the return rate is less than 20%.
Step 4 :Therefore, the correct hypotheses are: \(H_{0}: p=0.2\) and \(H_{1}: p<0.2\).
Step 5 :Final Answer: \(\boxed{H_{0}: p=0.2, H_{1}: p<0.2}\)