Error function
Error function
(OP)
I understand the basis of the math behind the error function (http://mathworld.wolfram.com/Erf.html) however...
Can anyone please explain in "engineering terms" what the error function is and how can I use it? I have found the erf(h/sqrt(2*s)) in the derivation of formula which involves gaussian distribution.
Thanks
Can anyone please explain in "engineering terms" what the error function is and how can I use it? I have found the erf(h/sqrt(2*s)) in the derivation of formula which involves gaussian distribution.
Thanks





RE: Error function
TTFN
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RE: Error function
http://en.wikipedia.org/wiki/Error_function
Any suggestions, thanks.
RE: Error function
RE: Error function
1-erf(h/sqrt(2*s))
I want to evaluate this equation numerically, how could I do that? Thanks, I am getting somewhere with this I think.
RE: Error function
RE: Error function
RE: Error function
Only you can tell what h and s are. The function is a solution to
d^2z/dh^2=2*dz/ds
which is a partial differential equation where I use the symbol "d" for the partial and d^2 the second partial.
Your link defines erf and from that and the parameters it should be easy to calculate or use tables for evaluation.
RE: Error function
erf(σ/sqrt(2)) = 95.45%, which is the same as ±2σ, so the form of the erf is identical to the integral from -2 to +σ of a gaussian distribution.
TTFN
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RE: Error function
P.S. Occupant, what software did you use to do the err evaluation? Is it MathCAD? I am currently using SMath Studio.
RE: Error function
SMath's GUI is more complicated than Mathcad's.
I guess I don't understand your comment here. Since you know what the error function does related to normal distributions, your specific question has been answered. The fact that you might not have a need to use it in your engineering doesn't mean that others also don't.
As I indicated above, I routinely use ERF in calculating probable distributions in my engineering area. A specific example is how large a physical area a munition might hit, given its dispersion, which is a measure of its statistical spread. There are, of course, other functions within Mathcad that do similar things, but ERF has the form that I prefer for that particular analysis.
TTFN
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