Optimal substitution of arguments of an arrangement increasing function based on sufficient statistics for parameters-arguments

The aim of this paper is to find the conditions under which optimal permutation of arguments of (goal) multivariate arrangement increasing functions of parameters of distributions must be realised, according to the same rule as if parameters-arguments ordering being the same as ordering of corresponding sufficient statistics.
Those results are used in the maximization problems of reliability of systems based on the test results of their components. Bibl. 16 titles.