开发者:上海品职教育科技有限公司 隐私政策详情

应用版本:4.2.11(IOS)｜3.2.5(安卓)APP下载

返回

*Baby 8 肖闲* · 2021年02月05日

问一道题：NO.PZ2015120604000137 [ CFA I ]

  1. CFA I
  2. Quantitative

问题如下：

Ida Lee and his team collect a lot of analysis of statistical data about the car market .According to the data, they come to the conclusion that the mean price of SUV is more than $46,435 in his country. Then they randomly select 64 SUVs whose mean price is $46,760. Assuming the standard deviation of the sample is 1370. Ida Lee conducts a hypothesis test to check their conclusion. At which significant level should Ida Lee reject the null hypothesis?

选项：

A.

0.5%.

B.

5%.

C.

1%.

解释：

B is correct.

If the significant level is 5%, the critical value=1.669<1.8978, Ida Lee should reject the null.

If the significant level is 0.5%, the critical value=2.656>1.8978, Ida Lee will fail to reject the null.

If the significant level is 1%, the critical value=2.387>1.8978, Ida Lee will fail to reject the null.


老师，这道题的原假设和备责假设分别都是什么呢？而且，我的理解是这个比较是单边的，如果是单边的话，那 level  是5%的话，对应的不是1。96 吗？还是我的理解上有什么错误？谢谢
添加评论
1 个答案
已采纳答案

星星_品职助教 · 2021年02月05日

同学你好，

这道题首先要建立原假设和备择假设，题干中描述“they come to the conclusion that the mean price of SUV is more than $46,435”，可以看出大于$46,435是Ida Lee相信并想去证明的。

建立假设的原则是“想要拒绝的放在原假设，想要证明的放在备择假设”

所以原假设是H0：μ≤46435，备择假设为Ha：μ＞46435。通过备择假设可以得到这是一个拒绝域在右侧的单尾的假设检验。

-----------------------

上课要求背的正态分布的关键值对应的都是 置信区间。例如1.96对应95%的置信区间.

在数量科目里，所有的置信区间都位于分布中央位置，所以左右两侧各有一个对称的“尾巴”。对于95%的置信区间而言，这两个尾巴的总面积是5%，所以单侧尾巴面积是2.5%。

如果单尾检验的 significant level=5%，说明单尾面积就是5%，所以这个时候正态分布的关键值就不是1.96了，而是1.65.

可以验证一下，1.65对应的是正态分布下90%的置信区间，所以双尾的面积为10%，单侧尾部面积即为5%。

这道题严格来说应该用t分布查表求关键值，不过一般这个值和正态的差别不是很大，所以对于非精细计算的题目，n很大时，用正态的关键值也可以去做判断。

  • 1

    回答

  • 0

    关注

  • 640

    浏览
相关问题

NO.PZ2015120604000137 问题如下 I Lee anhis tecollea lot of analysis of statisticta about the cmarket .Accorng to the tthey come to the conclusion ththe mepriof SUV is more th$46,435 in his country. Then they ranmly sele64 SUVs whose mepriis $46,760. Assuming the stanrviation of the sample is 1370. I Lee concts a hypothesis test to chetheir conclusion. whisignificant level shoulI Lee rejethe null hypothesis? A.0.5%. B.5%. C.1%. B is correct.If the significant level is 5%, the criticvalue=1.669 1.8978, I Lee shoulrejethe null.If the significant level is 0.5%, the criticvalue=2.656 1.8978, I Lee will fail to rejethe null.If the significant level is 1%, the criticvalue=2.387 1.8978, I Lee will fail to rejethe null. 请问此题需要记住t-test表的5%、1%、0.5%对应的数值吗？

2024-08-23 09:44 2 · 回答

NO.PZ2015120604000137问题如下 I Lee anhis tecollea lot of analysis of statisticta about the cmarket .Accorng to the tthey come to the conclusion ththe mepriof SUV is more th$46,435 in his country. Then they ranmly sele64 SUVs whose mepriis $46,760. Assuming the stanrviation of the sample is 1370. I Lee concts a hypothesis test to chetheir conclusion. whisignificant level shoulI Lee rejethe null hypothesis?A.0.5%.B.5%.C.1%.B is correct.If the significant level is 5%, the criticvalue=1.669 1.8978, I Lee shoulrejethe null.If the significant level is 0.5%, the criticvalue=2.656 1.8978, I Lee will fail to rejethe null.If the significant level is 1%, the criticvalue=2.387 1.8978, I Lee will fail to rejethe null.备择假设是小于，不应该是分布函数左侧面积，应该是小于关键值才才拒绝吗

2024-08-16 17:43 1 · 回答

NO.PZ2015120604000137 问题如下 I Lee anhis tecollea lot of analysis of statisticta about the cmarket .Accorng to the tthey come to the conclusion ththe mepriof SUV is more th$46,435 in his country. Then they ranmly sele64 SUVs whose mepriis $46,760. Assuming the stanrviation of the sample is 1370. I Lee concts a hypothesis test to chetheir conclusion. whisignificant level shoulI Lee rejethe null hypothesis? A.0.5%. B.5%. C.1%. B is correct.If the significant level is 5%, the criticvalue=1.669 1.8978, I Lee shoulrejethe null.If the significant level is 0.5%, the criticvalue=2.656 1.8978, I Lee will fail to rejethe null.If the significant level is 1%, the criticvalue=2.387 1.8978, I Lee will fail to rejethe null. 这是一个技术测试，谢谢。

2024-08-07 18:42 1 · 回答

NO.PZ2015120604000137 问题如下 I Lee anhis tecollea lot of analysis of statisticta about the cmarket .Accorng to the tthey come to the conclusion ththe mepriof SUV is more th$46,435 in his country. Then they ranmly sele64 SUVs whose mepriis $46,760. Assuming the stanrviation of the sample is 1370. I Lee concts a hypothesis test to chetheir conclusion. whisignificant level shoulI Lee rejethe null hypothesis? A.0.5%. B.5%. C.1%. B is correct.If the significant level is 5%, the criticvalue=1.669 1.8978, I Lee shoulrejethe null.If the significant level is 0.5%, the criticvalue=2.656 1.8978, I Lee will fail to rejethe null.If the significant level is 1%, the criticvalue=2.387 1.8978, I Lee will fail to rejethe null. 本题总体方差未知使用t检验，自由度是n-1，那计算标准误是使用n还是n-1

2024-08-04 11:07 1 · 回答

NO.PZ2015120604000137 问题如下 I Lee anhis tecollea lot of analysis of statisticta about the cmarket .Accorng to the tthey come to the conclusion ththe mepriof SUV is more th$46,435 in his country. Then they ranmly sele64 SUVs whose mepriis $46,760. Assuming the stanrviation of the sample is 1370. I Lee concts a hypothesis test to chetheir conclusion. whisignificant level shoulI Lee rejethe null hypothesis? A.0.5%. B.5%. C.1%. B is correct.If the significant level is 5%, the criticvalue=1.669 1.8978, I Lee shoulrejethe null.If the significant level is 0.5%, the criticvalue=2.656 1.8978, I Lee will fail to rejethe null.If the significant level is 1%, the criticvalue=2.387 1.8978, I Lee will fail to rejethe null. 这个t表 考试会给么 会明确表格是单尾还是双尾吗

2024-04-09 11:45 1 · 回答