Statistical instability of physical processes

New parameters describing destructions of statistical stability in finite observation interval have been proposed. For known and new statistical instability parameters, metric units that open possibility to characterize destructions of statistical stability in terms of quantity have been introduced. It is shown that essential rule in disturbances of statistical stability plays fluctuations of expectation of the process that lead to change expectation of average, and also fluctuations of variance of the process under definite parameter’s relationship. Change ranges of sampling value of parameters of statistical instability weakly depend from distribution type