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scalpa
France
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 Posted - 09/25/2012 : 06:22:29 AM
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Origin Ver. and Service Release (Select Help-->About Origin): 8.5 SR2
Operating System:win7
Hello,
I have a noisy curve on which the x are not evenly spaced (plus, there are several y for some xs).
I'd like to "bin" it ie have regularly spaced points that take the mean y value and I need the SD as well.
I'm sure it's there but I could not find it.
thanks for any clue.
best
scalpa |
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Hideo Fujii
USA
1582 Posts |
Posted - 09/25/2012 : 2:49:41 PM
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Hi scalpa,
To make a plot of X-evenly-spaced, mean-replaced-at-same-X plot, you can try the following:
1) Highlight Y column, and select "Statistics: Descriptive Statistics: Statistics on Columns".
In the tool's dialog, specify the X column as the "Grouping Range" under "Input Data> Range 1" option branch.
You can turn off unnecessary statistics like Sum, Min, Max, etc. You get the SD, etc.
in a flat report sheet, "DescStatsFlat1".
2) In this flat sheet, you can highlight unique X column, Mean column as Y, and SD column as yErr.
(If single point at an X position, SD would be "--" (missing value), and you can replace them to 0, if you like.)
3) Run "Interpolate/Extrapolate" menu under "Analysis: Mathematics" menu for the Mean plot
to produce the evenly spaced plot. (No way, but these rearranged points no longer have SD errors.)
Hope the above procedure works for your purpose.
--Hideo Fujii
OriginLab
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Edited by - Hideo Fujii on 09/25/2012 3:40:51 PM |
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scalpa
France
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Posted - 10/01/2012 : 12:38:35 PM
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HI Hideo,
thank you for response but this does not do the trick for me. I absolutely need the sd for each x. what i would like is : impose a bin size and within this bin (where I have several points), compute the average of the ys and the corresponding sd. (the xs are given by the binning and the origin).
any way to do this with origin ?
best
scalpa |
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Hideo Fujii
USA
1582 Posts |
Posted - 10/01/2012 : 3:14:54 PM
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Hi scalpa,
I think I got better understanding what you want. Could you please try the following procedure?
1) To aggregate the X values to equi-spaced series (with X Initial and X Increment),
add a column (col(C) below), and calculate the column by Set Column Values tool using the formula:
(Int((col(A)-IniX)/IncX))*IncX+iniX+(IncX/2)
2) Run the "Statistics on Columns" for Y (col(B) in my sample) with the above new column
as the Group Variable.
3) From "DescStatsFlat1" sheet, make a plot from X-Y-YErr.
Hope this matches to what you have envisioned.
--Hideo Fujii
OriginLab
P.S. As seen in the above screenshot, you can also get and use the SE (Standard Error of the mean) instead of SD. |
Edited by - Hideo Fujii on 10/01/2012 3:24:40 PM |
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scalpa
France
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Posted - 10/02/2012 : 04:09:54 AM
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Hi Hideo,
that's exactly it. Thank a lot !
all the best
scalpa |
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mean of a noisy curve