Kurtosis (the term first used by Pearson, 1905) measures the "peakedness" of a distribution. If the kurtosis is clearly different than 0, then the distribution is either flatter or more peaked than normal; the kurtosis of the normal distribution is 0. Kurtosis is computed as: Kurtosis = [n*(n+1)*M
4-3*M
2*M
2*(n-1)]/[(n-1)*(n-2)*(n-3)*
4]where M
j is equal to

(x
i-Mean
x)
jn is the valid number of cases
4 is the standard deviation (sigma) raised to the fourth power See also,
Descriptive Statistics .