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Urgent Help with error analysis required

  1. Nov 5, 2007 #1


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    1. The problem statement, all variables and given/known data

    I am trying to work out if there is an elegant way to do a line of best fit(straight) through a set of points (3) while taking into consideration their error bars? Clearly I'm looking for a piece of software that can do this. Obviously excel, etc can do a standard straight line + equation and add errors later on but the fit will be different if errors are considered in the place on each point individually.

    The reason i'm doing this is because I want to know the error in the gradient, taking account of the fact that each point has an error ( every point has different errors)

    3. The attempt at a solution

    The box method noted here will sort of work but it is quite tedious


    But I'm looking for alternative ways of doing this. I only have 3 points of data as well.

  2. jcsd
  3. Nov 6, 2007 #2
    You only have three points of data???!!?!?!

    There's your first problem.

    In the past I have used an error box method, but not the same as the one on the linked website.

    You have x error bars and y error bars - these can be made into error boxes around each data point.

    The line of maximum gradient then goes from the bottom right hand corner of your smallest x value to the top left corner of your highest x value.

    The line of minimum gradient goes from the top left of the smallest x error box to the bottom right of the highest x error box.

    Make sure that these lines go through ALL error boxes - if they don't, you have to make some adjustments.

    The points just mentioned and gradients are pretty easy to spit out of excel.

    Good luck.
  4. Nov 6, 2007 #3


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    I can't take any more points

    While i understand the box method, I was interested in a some sort of program being able to do the hard work for me lol

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