问题如下图:
选项:
A.
B.
C.
解释:
如何理解检验统计量的公式由来?
星星_品职助教 · 2020年04月16日
get你的问题了。这个公式的解释有一些超出CFA的范畴,教材上也是直接给出了公式。以双尾检验为例简单说一下,不需要掌握。
对于Z检验而言,根据中心极限定理,X bar服从均值为μ,方差为σ2/n的正态分布,所以可以把公式简单理解成一个正态分布的标准化,(X bar-μ)/(σ/√n)~N(0,1),即标准化后的结果服从标准正态分布。这个公式衡量了X bar到μ的距离是几倍的标准差,如果X bar对于总体均值μ的估计是正确的,则这个公式算出来的结果(距离)不应该很大。例如有95%的把握这个距离应该在1.96倍标准差的范围之内。如果超过了1.96,则说明随便抽样一次就发生了小概率事件,这种情况我们认为是不可能发生的,所以原假设错误,需要拒绝。
当总体方差σ未知的时候,由于s是σ的无偏估计量,所以在公式里用s代替,公式变为(X bar-μ)/(σ/√n)~t(n-1),即服从自由度为n-1的t分布。其余逻辑一致。
以上逻辑不需要掌握,考试也不会涉及。只需要根据标准化的思路记忆住公式即可。
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.老师可否展示下这个题的完整解题过程已经回答的答案感觉说的都是局部。谢谢
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?
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
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。
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