Dispersion parameter, definition estimation

A first approach to the definition of the confidence regions in parameter space follows the linear approximation to the parameter joint distribution that we have already used If the estimates are approximately normally distributed around 9 with dispersion [U. U.] then an approximate 100(1 - a)%... 

The International Vocabulary of Basic and General Terms in Metrology (VIM), second edition (ISO 1993a), defines uncertainty of measurement as the parameter, associated with the result of a measurement, that characterizes the dispersion of the values that could reasonably be attributed to the measurand (term 3.9). In the third edition (Joint Committee for Guides in Metrology 2007), the term measurement uncertainty is defined (term 2.27), and reasonably attributed is replaced by attributed to a measurand based on the information used. This definition emphasizes that the estimate of uncertainty is only as good as the information used to calculate it, so a report of an uncertainty should also state what information was used to calculate the uncertainty. 

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