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1·This tool is used to test the null hypothesis that there is no difference between two population means against either one-sided or two-sided alternative hypotheses.

此工具用于检验两个总体平均值之间不存在差异的空值假设，而不是单方或双方的其他假设。

2·The second one is two-sided hypothesis test problem.

第二个是双边假设检验问题。