两种错误，即：

The two types of errors are:

• α 错误，第一类错误（type I error ） ： 拒绝H₀时所犯的错误，它原本成立，但被拒绝。即侦察到本不存在的差异。
  

• α error(type I error): Rejecting the originally correct H₀. That is to say, discovering differences that do not originally exists.
  

• β 错误，第二类错误（type II error） ： 接受H₀时所犯的错误，它原本不成立，但被接受。即未能侦察到存在的差异。
  

• β error(type II error): Accepting the originally wrong H₀. That is to say, not discovering differences that originally exists.
  

在科学研究中，我们常常采取保守的策略，设定一个可接受的α水平来尽量减少I类错误。该α水平称为显著性水平。它规定了当虚无假设正确时，样本结果非常不可能出现的概率值。心理学研究中，α通常为0.05。 ^{1) 2)}

• In scientific research, we often adopt a conservative strategy to set an acceptable α level to minimize class I errors. This α level is called significance level. It specifies the probability that the sample result is very unlikely when the nothingness hypothesis is correct.In psychological research, it's usually 0.05.