  This paper is aimed to contribute to the scientific discussions that have
been triggered by the experimental observation of a quadratic relation between
the kurtosis and skewness of turbulent fluctuations present in fusion plasmas
and other nonlinear physical systems. In this paper we offer a general
statistical model which attributes the observed $K = aS^2 + b$ relation to the
varying intermittency of the experimental signals. The model is a two random
variable model constructed to catch the essential intermittent feature of the
real signal. One of the variables is the amplitude of the underlying
intermittent event (e.g. turbulent structure) while the other is connected to
the intermittency level of the system. This simple model can attribute physical
meaning to the $a$ and $b$ coefficients, as they characterize the
spatio-temporal statistics of intermittent events. By constructing a
particle-conserving Gaussian model for the underlying coherent structures the
experimentally measured $a$ and $b$ coefficients could be adequately
reproduced.
