level1 statistic中leptokurtic问题 cfa, kurtosis, statistics, level1

sumuyan3

notes第一册的statistical concepts and market returns 一节当中有一个课后题没看明白。a distribution that has a greater percentage of small deviations from the mean and a greater percentage of extremely large deviations from the mean will be leptokurtic and will exhibit excess kurtosis.
我的疑问在于，我认为如果small devations和extremely large devations都有greater percentage 的话，那么中间的devation就会小，就应该更平，应该是platykuritc。
忘解答，谢谢！！

amonliu

greater percentage of small deviations from the mean,说明离平均值更近的数更多，因而峰越尖，greater percentage of extremely large deviations from the mean，远离平均值的数更多，因而峰尾越大，因而中间的部分就小。导致，分布图比正态分布更高更尖，尾部更大，峰的中端更小，因而是leptokurtic

sumuyan3

回复 2# amonliu


   谢谢你！   其实只要有greater percentage of small deviaton from the mean这一句就已经可以判断是leptokuritic了对吧？