How Do I Calculate Uncertainty in Electrical Circuit Measurements?

[mathman100]

uncertainty equations??

can anyone help me here I'm dying over this! we did a lab and tomorrow I'm handing in my report, the last thing i have to do is find the uncertainties for my data, but i don't know what the uncertainty equations are! for example, one equation is R=V/I, or Rtotal=R1+R2+R3 , E=IVt, P+I^2R, 1/Rtotal=1/R1 +1/R2 +1/R3....any help?!??

 

[mathman100]

ok, i think i may have discovered how to do some of these, except maybe this one :
1/Rtotal=1/R1 +1/R2 +1/R3