- #1
charlesltl
- 5
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Hello Everyone,
I am trying to compute the standard error of a stress related calculation.
Let's consider the following:
A ± ΔA
B ± ΔB
where A and B are the mean values while ΔA and ΔB are the respective standard errors.
The common combination of errors formulas are as follows:
y = A + B then, Δy = √(ΔA2+ΔB2)
y = k. A then, Δy = k.ΔA
Now my equation is,
y = k2 . [ A + k1 . ( A + B + C ) ]
May I know if my following working is correct?
( A + B + C )
= √(ΔA2+ΔB2 + ΔC2)
k1 . ( A + B + C )
= k1 . √(ΔA2+ΔB2 + ΔC2)
A + k1 . ( A + B + C )
= √[ΔA2 + (k1 . √(ΔA2+ΔB2 + ΔC2))2]
= √[ΔA2 + k12 . (ΔA2+ΔB2 + ΔC2)]
k2 . [ A + k1 . ( A + B + C ) ]
= k2 . √[ΔA2 + k12 . (ΔA2+ΔB2 + ΔC2)]I am confused because I was suggested that it should be,
k2 . [ A + k1 . ( A + B + C ) ]
= k2 . √ [k1. ΔA2 + k12 . (ΔA2+ΔB2 + ΔC2)]
Your input in highly appreciated.
Charles
I am trying to compute the standard error of a stress related calculation.
Let's consider the following:
A ± ΔA
B ± ΔB
where A and B are the mean values while ΔA and ΔB are the respective standard errors.
The common combination of errors formulas are as follows:
y = A + B then, Δy = √(ΔA2+ΔB2)
y = k. A then, Δy = k.ΔA
Now my equation is,
y = k2 . [ A + k1 . ( A + B + C ) ]
May I know if my following working is correct?
( A + B + C )
= √(ΔA2+ΔB2 + ΔC2)
k1 . ( A + B + C )
= k1 . √(ΔA2+ΔB2 + ΔC2)
A + k1 . ( A + B + C )
= √[ΔA2 + (k1 . √(ΔA2+ΔB2 + ΔC2))2]
= √[ΔA2 + k12 . (ΔA2+ΔB2 + ΔC2)]
k2 . [ A + k1 . ( A + B + C ) ]
= k2 . √[ΔA2 + k12 . (ΔA2+ΔB2 + ΔC2)]I am confused because I was suggested that it should be,
k2 . [ A + k1 . ( A + B + C ) ]
= k2 . √ [k1. ΔA2 + k12 . (ΔA2+ΔB2 + ΔC2)]
Your input in highly appreciated.
Charles