THE EVALUATION OF THE UNCERTAINTY IN KNOWING A DIRECTLY MEASURED QUANTITY

This paper addresses the problem of evaluating the uncertainty in know ing a quantity measured directly with a measuring instrument. It is sh own that, under some conditions, the uncertainty associated with the u ncorrected result can be obtained from that associated with the correc tion. For this, the number of calibration measurements and the uncerta inty in knowing the value of the reference standard must be known by t he user of the instrument. The paper also discusses the evaluation of the uncertainty in case of indications corrected by an average of corr ection values over a given measurement range, and in case of a correct ion of null value.