S
shucksjay
Hello first time poster here. I have a measurement that is calculated by the formula z = a x b/(a + c). Each of the variables having a known uncertainty given in terms of standard deviations. Is the model equation the same as the formula to calculate the final value of z or is it something different?
I'm on the side that says the combined uncertainty is found by breaking the formula into three parts.
1. The a x b term
2. The a + c
3. The quotient of 1 and 2
The uncertainty of a x b would be Δx/x = sqrt[(Δa/a)^2 + (Δb/b)^2]
The uncertainty of a + c would just the RSS or Δy = sqrt(Δa^2 + Δb^2)
The combined uncertainty would then be Δz/z = sqrt[(Δx/x)^2 + (Δy/y)^2]
A colleague is on the side that the combined uncertainty is just the RSS of Δa, Δb, and Δc. They also don't agree with my approach to include the uncertainty of a in both equations 1 and 2.
I'm on the side that says the combined uncertainty is found by breaking the formula into three parts.
1. The a x b term
2. The a + c
3. The quotient of 1 and 2
The uncertainty of a x b would be Δx/x = sqrt[(Δa/a)^2 + (Δb/b)^2]
The uncertainty of a + c would just the RSS or Δy = sqrt(Δa^2 + Δb^2)
The combined uncertainty would then be Δz/z = sqrt[(Δx/x)^2 + (Δy/y)^2]
A colleague is on the side that the combined uncertainty is just the RSS of Δa, Δb, and Δc. They also don't agree with my approach to include the uncertainty of a in both equations 1 and 2.