若X是来自正态分布的一个样本，其样本量为20，样本均值为10.2，样本标准差为10，那么它的（95%）的置信区间的下界为（保留2位小数点）？已知
=-1.96，
(19)=-1.73.（ ）
A: 5.82
B: 5.70
C: 6.33
D: 6.23
=-1.96，(19)=-1.73.（ ）A: 5.82
B: 5.70
C: 6.33
D: 6.23
举一反三
- 若X是来自正态分布的一个样本，其样本量为20，样本均值为10.2，样本标准差为10，那么它的（95%）的置信区间的下界为（保留2位小数点）？已知[img=50x21]17d624cc6b49c50.png[/img]=-1.96，[img=46x25]17d624cc7a8d3ce.png[/img](19)=-1.73.（ ） A: 5.82 B: 5.70 C: 6.33 D: 6.23
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