Coherence coefficients as uncertainty parameters of error value set

Arithmetical operations performed on measurement results treated as intervals cause that the influence both errors distribution shape and errors correlation to the width of the resultant interval must be considered. The paper describes the use of reductive interval arithmetic [2] in such a situation. Coherence coefficients which generally describe interdependence between intervals are interpreted as parameters of the error value set. The composition rule for two kinds of coefficients-those dependent on the shapes of the error distributions and those dependent on correlation between errors-is presented. Uncertainty calculation inaccuracy of the described method has been analysed in the paper, too.