Chronology Current Month Current Thread Current Date
[Year List] [Month List (current year)] [Date Index] [Thread Index] [Thread Prev] [Thread Next] [Date Prev] [Date Next]

Re: [Phys-L] Sig Figs homework from my 7th grader

On 10/9/2013 8:49 AM, Paul Nord wrote:
I know the answer the teacher wants, but i find it troubling...

10.53 + 0.615 = ?

Share and enjoy,
Paul
_______________________________________________


Supposing I were troubled by the desire to best represent the last figure uncertainty, I might proceed in this way:
10.53 +-0.005
0.615 +-0.0005
==============
11.1450 +-0.0050 +-0.0005 = 11.1445 to 11.1505 or 11.1475 +- 0.0030

It is this last line that would prove worrying: why should the nominal value shift, when the last figure uncertainties are accounted for?

Brian Whatcott Altus OK