Coefficient of Kurtosis

Kurtosis is a measure of the sharpness of the data peak. Traditionally the value of this coefficient is compared to a value of 0.0, which is the coefficient of kurtosis for a normal distribution, i.e., the bell-shaped curve. A value greater than 0 indicates a peaked distribution and a value less than 0 indicates a flat distribution. Without a very large sample size, the use of this coefficient is of questionable value.

Population Kurtosis ( $image\kurt-y2.png$ )

$image\popkurt.png$

Sample Kurtosis ( $image\kurt-g2.png$ )

$image\samkurt.png$

(adapted from King and Julstrom, 1982)

where

$image\popsd-sym.png$	= Population Standard Deviation
S	= Sample Standard Deviation
$image\u.png$	= Population Mean
$image\mean.png$	= Sample Mean
N	= number of data values for a population
n	= number of data values for a sample
xi	= ith data value

Coefficient of Kurtosis

See Also