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vee · 2022年11月28日

A为什么不对

  1. CFA I
  2. Quantitative

NO.PZ2017092702000141

问题如下：

A pooled estimator is used when testing a hypothesis concerning the:

选项：

A.

equality of the variances of two normally distributed populations.

B.

difference between the means of two at least 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.

解释：

B is correct.

The assumption that the variances are equal allows for the combining of both samples to obtain a pooled estimate of the common variance.

如下图所示，这是一个POOLED ESTIMATOR。

之所以为POOLED，可以理解为在等式右边需要同时用到S1以及S2两个不同样本的方差。而上图的公式，是T检验中一步，这个T检验就是检验B选项说论述的假设检验。


为什么A不对？a不是表达方差相等吗

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1 个答案

星星_品职助教 · 2022年11月28日

同学你好，

题目“A pooled estimator is used when testing a hypothesis concerning the......”问的是pooled estimator用在哪种假设检验里。

pooled estimator用在检验两个均值是否相等的t检验中，即检验的是两个均值之间的关系。

而A选项检验的是两个方差，这种检验（F检验）里不会用到pooled estimator。

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NO.PZ2017092702000141 问题如下 A pooleestimator is usewhen testing a hypothesis concerning the: A.equality of the variances of two normally stributepopulations. B.fferenbetween the means of two least approximately normally stributepopulations with unknown but assumeequvariances. C.fferenbetween the means of two least approximately normally stributepopulations with unknown anassumeunequvariances. B is correct. The assumption ththe variances are equallows for the combining of both samples to obtain a pooleestimate of the common variance.如下图所示，这是一个POOLEESTIMATOR。之所以为POOLE可以理解为在等式右边需要同时用到S1以及S2两个不同样本的方差。而上图的公式，是T检验中一步，这个T检验就是检验B说论述的假设检验。 B C but an一词之差，可以下表达意思有什么不同吗？

2023-02-27 23:11 1 · 回答

NO.PZ2017092702000141 fferenbetween the means of two least approximately normally stributepopulations with unknown but assumeequvariances. fferenbetween the means of two least approximately normally stributepopulations with unknown anassumeunequvariances. B is correct. The assumption ththe variances are equallows for the combining of both samples to obtain a pooleestimate of the common variance. 如下图所示，这是一个POOLEESTIMATOR。 之所以为POOLE可以理解为在等式右边需要同时用到S1以及S2两个不同样本的方差。而上图的公式，是T检验中一步，这个T检验就是检验B说论述的假设检验。 不应该是不同的方差吗？答案不是C？

2021-08-27 18:49 1 · 回答

NO.PZ2017092702000141 请问这样的知识点是不是算比较偏的，是不是考点呀

2021-08-26 20:45 1 · 回答

NO.PZ2017092702000141 完全读不懂。。。

2021-02-06 23:27 1 · 回答