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Homework Help: Least-squares parabola

  1. Oct 22, 2004 #1
    I have tried to find some information of the expresions for a least-squares parabola coefficients (including their uncertaintities), then I have tried to do it for myself using the minimum condition for partial derivatives as same as with the least-squares line, but the expressions of coefs are so complex, and then I have no idea to obtain uncertaintities. In Matlab are a function to get the coefficients but not the uncertaintities, and I am upset, since I must get how to obtain uncertaintities, it's fundamental for a lab report on Maxwell's Disc.

    Please Help Me!!
  2. jcsd
  3. Oct 23, 2004 #2
    For the linear least-squares regression we can get:




    and their uncertaintities:



    where D=(Σ(x^2)-n(xmean^2)). hence we have that the ecuation is:


    Well I'm triying to do the same for a parabolic least-squares.
  4. Oct 23, 2004 #3
    for a parabolic least squares, you need to use logarithms.
  5. Oct 23, 2004 #4
    plot you graph on log paper. it should make a stright line.
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