  Both classical and respectively quantum observables can be modeled as
somewhat similar examples of random variables. In such a model the associated
measurements preserve the values spectrum of an observable but change the
corresponding probabilistic weights (probability density or respectively the
wave function). Such a model ensures theoretical estimations for predicted
errors specific to the mean values as well as to the fluctuations of both types
of observables. The model stands out of ourdays prevalent opinion that
measurement theories must be depicted in entirely different manners in the
classical respectively quantum cases.
