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This category contains results about Kurtosis.
Definitions specific to this category can be found in Definitions/Kurtosis.

Definition 1

The kurtosis of $X$ is the fourth standardized moment of $X$:

$\alpha_4 = \expect {\paren {\dfrac {X - \mu} \sigma}^4}$

where $\expect {\, \cdot \,}$ denotes expectation.

Definition 2

The kurtosis of $X$ is defined as:

$\alpha_4 = \dfrac {\mu_4} {\paren {\mu_2}^2}$

where $\mu_i$ denotes the $i$th central moment of $X$.