题目
What is kurtosis? What is its role in statistical distributions?
选项
A.Kurtosis measures the nature of the spread of the values around the mean. It represents the 4th moment of a distribution. A large kurtosis indicates a sharp peak in the middle of a distribution. A population with high kurtosis is usually called leptokurtic. The kurtosis plays an important role in distinguishing those distributions that place additional probability on larger values.
B.Kurtosis represents the 3rd moment of a distribution. A small kurtosis indicates flatness in the middle of the distribution. A population with low kurtosis is usually called leptokurtic. Skewness (and not kurtosis) plays an important role in distinguishing those distributions that place additional probability on larger values.
C.Kurtosis can be verified in the four initial moments of a distribution and measures the mean of a distribution.
D.Kurtosis can be seen in the second and fourth moments of a distribution and measures the standard deviation of a distribution.
答案
A
解析
Kurtosis measures the nature of the spread of values around the mean (4th moment). 峰度度量的是均值附近的扩散性质（四阶矩）。