刘同学2024-07-22 21:56:37
刘同学A pooled estimator is used when testing a hypothesis concerning the:A.equality of the variances of two normally distributed populations.B.difference between the means of two approximately normally distributed populations with unknown but assumed equal variances.C.difference between the means of two at least approximately normally distributed populations with unknown and assumed unequal variances.这道题没太明白啥意思
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Bingo2024-08-14 17:52:40
Bingo同学你好，
A pooled estimator is used when testing a hypothesis concerning the:
A.equality of the variances of two normally distributed populations.
B.difference between the means of two approximately normally distributed populations with unknown but assumed equal variances.
C.difference between the means of two at least approximately normally distributed populations with unknown and assumed unequal variances.
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同学你好，
如图，Sp的平方就是pooled estimator（综合估计量），是在：
1.检验两个正太分布的总体均值是否相等
2.其中总体方差未知但是假定相等
这两个条件下使用的
考纲不要求掌握其公式，但是题目如果给出公式，要求会带入数值计算的，定性方面需要了解截图内的描述。
题目：
当检验以下哪一个假设时，使用综合估计量(pooled estimator)：B
A 两个正态分布的方差是否相等。
B 两个近似正态分布的总体均值是否相等，方差未知但假设相等。
C 两个近似正态分布的总体均值是否相等，方差未知但假设不相等。
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