There are various kinds of nonparametric tests. In this paper, we consider testing population mean, using the empirical likelihood ratio test. The empirical likelihood ratio test is useful in a large sample, but it has size distortion in a small sample. For size correction, various corrections have been considered. Here, we utilize the Bartlett correction and the bootstrap method. The purpose of this paper is to compare the t test and the empirical likelihood ratio tests with respect to the sample power as well as the empirical size through Monte Carlo experiments.