tolerance: how to add measurements with tolerances

[Paul Suszko]

I have forgotten how to add the following tolerances:

66 +/- 3.0 g
20 +/- 2.0 g
14 +/- 1.73 g

I am to arrive at a total value of 100 +/- 4.00 g.

Thank you.

 

[royhaas]

Square the individual tolerances; add them together; take the square root of the result.

 

[tkhunny]

Maybe $\displaystyle \sqrt{3^{2}+2^{2}+(\sqrt{3})^{2}}\;=\;\sqrt{9+4+3}\;=\;\sqrt{16}\;=\;4$? I wouldn't exactly call that addition, per se.

 

[Paul Suszko]

Thanks.