The confidence interval for the ratio p is one of the mandatory and necessary knowledge in the curriculum of the Statistics Probability module at the university level. There are many methods for estimating CIs for different rates, but the CI most used in statistical probability textbooks in Vietnam that we refer to is the Wald CI because of its simplicity in calculation and application in practice. international. However, the conditions for use of the Wald CI must be satisfied, otherwise the estimated CI for the population will be inaccurate and even have no use value such as CI containing negative values or exceeding 1.This article presents some alternative methods in teaching when the conditions of the Wald CI are not satisfied through an illustrative example with the support of Stata 17 software.