For Any Frequency Distribution The Kurtosis Is Equal To. For unbounded skew distributions not too far from normal κ tends to be somewhere in the area of γ2 and 2γ2. What does it mean when kurtosis is negative.
The excess kurtosis is equal to 0 the distribution is called mesokurtic. As Alecos notes in comments some people define kurtosis as E Z 4 3. This statistic is standardized so that a normal distribution 5 has a kurtosis of 0.
As you note this fourth standardized moment is 3 in the case of a normal random variable.
The normalized excess is given by κ μ 4 σ 4 3. This means that the frequency of observations on both sides is equal. As the kurtosis of a mesokurtic distribution is neither positive nor negative it serves as a baseline for the two other categories. Then the data distribution is mesokurtic.
