PLEASE NOTE:
This document has been withdrawn as it is based on the 1993 edition of the Guide to the expression of uncertainty in measurement (GUM). ISO has recently republished the 1995 (corrected) edition of the GUM as ISO/IEC Guide 98-3:2008. The relevant BSI committee has decided not to adopt the 2008 edition of the GUM as a BSI Published Document.
Printed copies of ISO/IEC Guide 98-3:2008 are available for purchase from BSI Customer Services.