我理解是n小的时候是t，n大的时候t和z都可以，为什么这里n大的时候是t，如果t可以那z也可以不是么
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No.PZ2018062016000137 (选择题)
来源: 品职出题
Assume that the varience is unknown, which of the following statements on a hypothesis tests of the population mean is most accurate?
您的回答, 正确答案是: B
A
不正确If the sample is small, it's a t-test.
B
If the sample is large, it's a t-test.
C
If the sample is small, it's a z-test.
数据统计(全部)
做对次数: 751
做错次数: 843
正确率: 47.11%
数据统计(个人)
做对次数: 0
做错次数: 1
正确率: 0.00%
解析
B is correct. If the population sampled has unknown variance, the sample is large, or the sample is small but the population sampled is normally distrubuted, or approximately normally distributed, then the test statistic for hypothesis tests concerning a single population mean.
