Help with Excel trendlines

Discussion in 'Mac Apps and Mac App Store' started by plunar, Apr 10, 2007.

  1. plunar macrumors 6502

    plunar

    Joined:
    Sep 7, 2003
    #1
    Excel's trendline options are rather pathetic.

    I do not know why, but in the trendline options excel has the logarithmic curves option greyed out. However, these data are clearly suited for a logarithmic curve. why is excel giving me a hard time? these curves are not polynominals!
     

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  2. clevin macrumors G3

    clevin

    Joined:
    Aug 6, 2006
    #2
    if its logarithm, it might be better u change the x axis to logarithm, so u get a near straight line.
     
  3. plunar thread starter macrumors 6502

    plunar

    Joined:
    Sep 7, 2003
    #3
  4. balamw Moderator

    balamw

    Staff Member

    Joined:
    Aug 16, 2005
    Location:
    New England
    #4
    What happens if you make your y axis start at something other than zero (and make sure you have no zeros in your data)?

    Since the log of zero or a negative number diverge or are undefined, MS greys the option out.

    Still, I agree Excel is lousy for XY plots.

    B
     
  5. plunar thread starter macrumors 6502

    plunar

    Joined:
    Sep 7, 2003
    #5
    okay so taking out the first row, where x values equal zero, fixed the trendlines. they still are lousy fits though. is there another program (free) i can use for this?
     
  6. iSaint macrumors 603

    iSaint

    Joined:
    May 26, 2004
    Location:
    South Mississippi y'all, near the water!
    #6
    Grapher is on my G4 Powerbook under Applications > Utilities. Check that location...
     
  7. balamw Moderator

    balamw

    Staff Member

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    Aug 16, 2005
    Location:
    New England
  8. MisterMe macrumors G4

    MisterMe

    Joined:
    Jul 17, 2002
    Location:
    USA
    #8
    Not to belabor the obvious, but as a charting application Excel is very blunt intrument. There are dedicated charting apps which do a beautiful job with Excel data. My personal favorite is KaleidaGraph. Many swear by DeltaGraph which specializes in graphing Excel data. You can find other charting apps here and there.
     

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