# Max possible error in this addition

• Feb 3rd 2009, 02:02 PM
mike_302
Max possible error in this addition
Okay so the homework is FROM physics, but its 100% math.

Q: Find the max possible error or (absolute) uncertainty for the following measurements --> 4.5 +/- .5 m + 1.5 +/- .5 m

Solution:

So my first and only thought would be to add the uncertainties but there is no answer so I don't know.... i.e. in this case, .5 + .5 = 1.0m Therefore max possible uncertainty would be 1.0m ..

Can anyone confirm, deny, correct me ?
• Feb 3rd 2009, 03:26 PM
Soroban
Hello, mike_302!

Quote:

Find the max possible error or (absolute) uncertainty for the following measurements: .$\displaystyle (4.5 \pm 0.5) + (1.5 \pm0.5)$ meters.

The maximum error occurs in two ways.

Both measurements are over by 0.5 m.
. . The error would be: $\displaystyle +1.0\text{ m.}$

Both measurements are under by 0.5 m.
. . The error would be: $\displaystyle -1.0\text{ m.}$

The maximum error would be: .$\displaystyle \pm1.0\text{ m}$

. . Off by as much as a meter in either direction.
.
• Feb 3rd 2009, 03:36 PM
mike_302
Okay so really you are just adding the two "max possible error" values... and if they were +/- .3 and +/- .6 respectively, then the max possible error in the addition would be +/- .9 .

Thank you very much ! =D