Abstract
In this paper we describe statistical test. This is the most important statistical field for examining the mean, variance and other characteristics of population by using sample. First, we propose a null hypothesis, for example, that the population mean is a certain value. With statistical analysis, if we conclude that the null hypothesis is to be rejected, we judge that the hypothesis is probably not true. When we conclude that the null hypothesis is to be accepted, we can only say that we cannot reject it. In this paper, we also describe a test of independence. This is a method of testing, for example, whether we can recognize a difference in the numbers of male and female patients with certain diseases. The main method of testing for independence is not applicable to small samples, for which other methods must be used.
