ANALYSIS OF APPROACHES TO EFFECTIVE DEGREES OF FREEDOM ESTIMATION IN THE PRESENCE OF OBSERVED CORRELATION BETWEEN THE RESULTS OF MEASUREMENT OF INPUT QUANTITIES

One of the main principles of evaluating expanded uncertainty in the Guide to the Expression of Uncertainty in Measurement (GUM) in the presence of significant contributions of type A uncertainty is to assign to the measurand the t-distribution with degrees of freedom determined by the Welch-Satterthwaite equation.