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Fitting of xy data

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  • January 14, 2005 at 12:45 am #12668
    detemple@physik.rwth-aachen.dedetemple@physik.rwth-aachen.de
    Participant

    I tried to fit a dataset consisting of 4 xy data-pairs. The data are as follows:

    x: 10/11/12/13
    y: 100/121/144/169

    I selected constant & X & X^2 for fitting this set. I expected: Y=X^2

    But FlexPro says: Best fit is achievd with: Y=100+20*X+1*X^2

    Can anybody explain this bad fitting? Is there any trick when using the “Kurvenanpassung”?
    The program “Origin” has no problem finding the solution Y=X^2.

    January 14, 2005 at 1:25 am #9085
    Bernhard KantzBernhard Kantz
    Participant

    If you have seperate data sets for the X and the Y-components for the approximation you must select this option on the Data tab of the Approximation property sheet and insert the two data sets.

    Otherwise FlexPro creates the X-component with the starting value 0 and the increment 1.

    Support@weisang.com

    January 14, 2005 at 3:57 am #9086
    detemple@physik.rwth-aachen.dedetemple@physik.rwth-aachen.de
    Participant

    Thanks for the answer.

    Now it works. Are the features “Kurvenanpassung” and “Statistik/Regression” included in the FlexPro 6 View or in the FlexPro 6 Standard version?

    January 14, 2005 at 6:16 pm #9087
    Bernhard KantzBernhard Kantz
    Participant

    The curve fitting objects and the statistics objects Maximum, Minimum, Regression, RMS and Quanitity are included in FlexPro 6 Standard.

    To see all available FPScript-Functions and all available Analyis Objects respectively and to which option they belong, please open the FlexPro Online Help and select “Analyzing Data/Reference/Functions” and “Analyzing Data/Reference/Analysis Objects respectively . This pages lists all functions or analysis objects along with the Options they belong to. There are additional options (advanced statistics, counting procedures, order tracking, spectral analysis, acoustics) which are no part of FlexPro Standard or FlexPro Professional.

    See also http://www.weisang.com/text/22010200_0000.htm

    Support@weisang.com

    January 14, 2005 at 6:16 pm #8331
    detemple@physik.rwth-aachen.dedetemple@physik.rwth-aachen.de
    Participant

    I tried to fit a dataset consisting of 4 xy data-pairs. The data are as follows:

    x: 10/11/12/13
    y: 100/121/144/169

    I selected constant & X & X^2 for fitting this set. I expected: Y=X^2

    But FlexPro says: Best fit is achievd with: Y=100+20*X+1*X^2

    Can anybody explain this bad fitting? Is there any trick when using the “Kurvenanpassung”?
    The program “Origin” has no problem finding the solution Y=X^2.

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