Quote Originally Posted by namlexuannth View Post
Dear All*
I post to seek your consultance/experiences for explaination about the Uncertainty value in the attached certificate.

Example:

Standard value (ARV) = 0.0502%
Uncertainty (U) =2

I cannot understand that U >> much more than ARV* because U value here is not defined the fomular. There fore* Does this certificate is wrong?

Could anyone understand* plesease help to share it. Especially* if you have any standard related to clear this problems* also open share it.

I'm so appreciate*
standard value +- uncertainty value

i.e. methane 0.0502% +- 2%* can be between 0.0502 -2%=0.0492 and 0.0502+2%=0.0512