问题如下图:
选项:
A.
B.
C.
D.
答案说T分布有更高的峰度,说反了吧
NO.PZ2016062402000014 问题如下 Whiof the following statements is the most accurate about the relationship between a normstribution ana Stunt’s t stribution thhave the same meanstanrviation? A.They have the same skewness anthe same kurtosis. B.The Stunt’ t stribution hlarger skewness anlarger kurtosis. C.The kurtosis of a Stunts t stribution converges to thof the normstribution the number of grees of freem increases. The normstribution is a gooapproximation for the Stunt’s t stribution when the number of grees of freem is small. The two stributions have the same skewness of zero but the Stunt’ t hlower kurtosis. the number of grees of freem increases, the Stunt’s t stribution converges to the normstribution, so C is the correanswer. t分布正常是比正态分布离散的,题目里说T和Z方差一致时,我理解就是n已经大到T趋近于Z的情况了,为什么A不对呢
NO.PZ2016062402000014 The Stunt’ t stribution hlarger skewness anlarger kurtosis. The kurtosis of a Stunts t stribution converges to thof the normstribution the number of grees of freem increases. The normstribution is a gooapproximation for the Stunt’s t stribution when the number of grees of freem is small. The two stributions have the same skewness of zero but the Stunt’ t hlower kurtosis. the number of grees of freem increases, the Stunt’s t stribution converges to the normstribution, so C is the correanswer.老师,按照T分布的峰度公式,3(n-2)/(n-4),不是应该大于3吗?应该比这正态分布的峰高才是啊,为什么是低峰肥尾呢?
正态分布与t分布,在两者的均值与标准差相同的时候,相对于正态分布,t分布峰度低,并且尾部肥,对吗?那么,在讲Kurtosis的时候,假设方差相同,得出的结论是低峰→薄尾。不矛盾吗?请问老师,我是哪里理解错了?
自由度决定什么呢?他的增加改变了高度?
老师你好,请问什么不对呢?增大,t分布趋近于Z分布,过来说不可以吗?