Uncertainties Due to Imperfect Knowledge of Systematic Eeects: General Considerations and Approximate Formulae

Starting from considerations about meaning and subsequent use of asymmetric uncertainty intervals of experimental results, we review the issue of uncertainty propagation. We show that, using a probabilistic approach (the so-called Bayesian approach), all sources of uncertainty can be included in a logically consistent way. Practical formulae for the rst moments of the probability distribution are derived up to second-order approximations.