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Excel Function to Match Power Trendline in Chart?

  1. #1
    Registered User
    Join Date
    06-21-2005
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    Excel Function to Match Power Trendline in Chart?

    Hi,

    I'm using the "Power" trendline in an XY scatter chart and want to use the formula and the rsquared result in a worksheet.

    What worksheet function can I use to to show the function (or it's components) and the rsquared within the worksheet?

    (The formula stated on the chart is: y = 644.691x^-0.895)

    I've looked at LINEST but that seems to only give a straight line trend?

    LOGEST gives me the exponential result?

    Basically I'm worried about using the rsquared value from the chart if I don't have it through a function as well.

    Anyone able to help?

    Thanks!

  2. #2
    Jerry W. Lewis
    Guest

    Re: Excel Function to Match Power Trendline in Chart?

    Despite extremely misleading text in Help, LINEST is not limited to
    straight lines; it fits models that are linear in the unknown
    coefficients (polynomials, etc.), cf.
    http://www.stfx.ca/people/bliengme/E...Polynomial.htm
    If y=a*x^b then ln(y)=ln(a)+b*ln(x), which the chart trendline uses to
    estimate the coefficients. In that second form, you can use LINEST, or
    SLOPE, INTERCEPT, and RSQ. If you do not have Excel 2003,
    http://groups-beta.google.com/group/...e7a1c650?hl=en
    suggests alternate calculations that will be more accurate in certain
    circumstances.

    Jerry

    acjim wrote:

    > Hi,
    >
    > I'm using the "Power" trendline in an XY scatter chart and want to use
    > the formula and the rsquared result in a worksheet.
    >
    > What worksheet function can I use to to show the function (or it's
    > components) and the rsquared within the worksheet?
    >
    > (The formula stated on the chart is: y = 644.691x^-0.895)
    >
    > I've looked at LINEST but that seems to only give a straight line
    > trend?
    >
    > LOGEST gives me the exponential result?
    >
    > Basically I'm worried about using the rsquared value from the chart if
    > I don't have it through a function as well.
    >
    > Anyone able to help?
    >
    > Thanks!



  3. #3
    Jerry W. Lewis
    Guest

    Re: Excel Function to Match Power Trendline in Chart?

    Despite extremely misleading text in Help, LINEST is not limited to
    straight lines; it fits models that are linear in the unknown
    coefficients (polynomials, etc.), cf.
    http://www.stfx.ca/people/bliengme/E...Polynomial.htm
    If y=a*x^b then ln(y)=ln(a)+b*ln(x), which the chart trendline uses to
    estimate the coefficients. In that second form, you can use LINEST, or
    SLOPE, INTERCEPT, and RSQ. If you do not have Excel 2003,
    http://groups-beta.google.com/group/...e7a1c650?hl=en
    suggests alternate calculations that will be more accurate in certain
    circumstances.

    Jerry

    acjim wrote:

    > Hi,
    >
    > I'm using the "Power" trendline in an XY scatter chart and want to use
    > the formula and the rsquared result in a worksheet.
    >
    > What worksheet function can I use to to show the function (or it's
    > components) and the rsquared within the worksheet?
    >
    > (The formula stated on the chart is: y = 644.691x^-0.895)
    >
    > I've looked at LINEST but that seems to only give a straight line
    > trend?
    >
    > LOGEST gives me the exponential result?
    >
    > Basically I'm worried about using the rsquared value from the chart if
    > I don't have it through a function as well.
    >
    > Anyone able to help?
    >
    > Thanks!



  4. #4
    Jerry W. Lewis
    Guest

    Re: Excel Function to Match Power Trendline in Chart?

    Despite extremely misleading text in Help, LINEST is not limited to
    straight lines; it fits models that are linear in the unknown
    coefficients (polynomials, etc.), cf.
    http://www.stfx.ca/people/bliengme/E...Polynomial.htm
    If y=a*x^b then ln(y)=ln(a)+b*ln(x), which the chart trendline uses to
    estimate the coefficients. In that second form, you can use LINEST, or
    SLOPE, INTERCEPT, and RSQ. If you do not have Excel 2003,
    http://groups-beta.google.com/group/...e7a1c650?hl=en
    suggests alternate calculations that will be more accurate in certain
    circumstances.

    Jerry

    acjim wrote:

    > Hi,
    >
    > I'm using the "Power" trendline in an XY scatter chart and want to use
    > the formula and the rsquared result in a worksheet.
    >
    > What worksheet function can I use to to show the function (or it's
    > components) and the rsquared within the worksheet?
    >
    > (The formula stated on the chart is: y = 644.691x^-0.895)
    >
    > I've looked at LINEST but that seems to only give a straight line
    > trend?
    >
    > LOGEST gives me the exponential result?
    >
    > Basically I'm worried about using the rsquared value from the chart if
    > I don't have it through a function as well.
    >
    > Anyone able to help?
    >
    > Thanks!



  5. #5
    Jerry W. Lewis
    Guest

    Re: Excel Function to Match Power Trendline in Chart?

    Despite extremely misleading text in Help, LINEST is not limited to
    straight lines; it fits models that are linear in the unknown
    coefficients (polynomials, etc.), cf.
    http://www.stfx.ca/people/bliengme/E...Polynomial.htm
    If y=a*x^b then ln(y)=ln(a)+b*ln(x), which the chart trendline uses to
    estimate the coefficients. In that second form, you can use LINEST, or
    SLOPE, INTERCEPT, and RSQ. If you do not have Excel 2003,
    http://groups-beta.google.com/group/...e7a1c650?hl=en
    suggests alternate calculations that will be more accurate in certain
    circumstances.

    Jerry

    acjim wrote:

    > Hi,
    >
    > I'm using the "Power" trendline in an XY scatter chart and want to use
    > the formula and the rsquared result in a worksheet.
    >
    > What worksheet function can I use to to show the function (or it's
    > components) and the rsquared within the worksheet?
    >
    > (The formula stated on the chart is: y = 644.691x^-0.895)
    >
    > I've looked at LINEST but that seems to only give a straight line
    > trend?
    >
    > LOGEST gives me the exponential result?
    >
    > Basically I'm worried about using the rsquared value from the chart if
    > I don't have it through a function as well.
    >
    > Anyone able to help?
    >
    > Thanks!



  6. #6
    Jerry W. Lewis
    Guest

    Re: Excel Function to Match Power Trendline in Chart?

    Despite extremely misleading text in Help, LINEST is not limited to
    straight lines; it fits models that are linear in the unknown
    coefficients (polynomials, etc.), cf.
    http://www.stfx.ca/people/bliengme/E...Polynomial.htm
    If y=a*x^b then ln(y)=ln(a)+b*ln(x), which the chart trendline uses to
    estimate the coefficients. In that second form, you can use LINEST, or
    SLOPE, INTERCEPT, and RSQ. If you do not have Excel 2003,
    http://groups-beta.google.com/group/...e7a1c650?hl=en
    suggests alternate calculations that will be more accurate in certain
    circumstances.

    Jerry

    acjim wrote:

    > Hi,
    >
    > I'm using the "Power" trendline in an XY scatter chart and want to use
    > the formula and the rsquared result in a worksheet.
    >
    > What worksheet function can I use to to show the function (or it's
    > components) and the rsquared within the worksheet?
    >
    > (The formula stated on the chart is: y = 644.691x^-0.895)
    >
    > I've looked at LINEST but that seems to only give a straight line
    > trend?
    >
    > LOGEST gives me the exponential result?
    >
    > Basically I'm worried about using the rsquared value from the chart if
    > I don't have it through a function as well.
    >
    > Anyone able to help?
    >
    > Thanks!



  7. #7
    Jerry W. Lewis
    Guest

    Re: Excel Function to Match Power Trendline in Chart?

    Despite extremely misleading text in Help, LINEST is not limited to
    straight lines; it fits models that are linear in the unknown
    coefficients (polynomials, etc.), cf.
    http://www.stfx.ca/people/bliengme/E...Polynomial.htm
    If y=a*x^b then ln(y)=ln(a)+b*ln(x), which the chart trendline uses to
    estimate the coefficients. In that second form, you can use LINEST, or
    SLOPE, INTERCEPT, and RSQ. If you do not have Excel 2003,
    http://groups-beta.google.com/group/...e7a1c650?hl=en
    suggests alternate calculations that will be more accurate in certain
    circumstances.

    Jerry

    acjim wrote:

    > Hi,
    >
    > I'm using the "Power" trendline in an XY scatter chart and want to use
    > the formula and the rsquared result in a worksheet.
    >
    > What worksheet function can I use to to show the function (or it's
    > components) and the rsquared within the worksheet?
    >
    > (The formula stated on the chart is: y = 644.691x^-0.895)
    >
    > I've looked at LINEST but that seems to only give a straight line
    > trend?
    >
    > LOGEST gives me the exponential result?
    >
    > Basically I'm worried about using the rsquared value from the chart if
    > I don't have it through a function as well.
    >
    > Anyone able to help?
    >
    > Thanks!



  8. #8
    Jerry W. Lewis
    Guest

    Re: Excel Function to Match Power Trendline in Chart?

    Despite extremely misleading text in Help, LINEST is not limited to
    straight lines; it fits models that are linear in the unknown
    coefficients (polynomials, etc.), cf.
    http://www.stfx.ca/people/bliengme/E...Polynomial.htm
    If y=a*x^b then ln(y)=ln(a)+b*ln(x), which the chart trendline uses to
    estimate the coefficients. In that second form, you can use LINEST, or
    SLOPE, INTERCEPT, and RSQ. If you do not have Excel 2003,
    http://groups-beta.google.com/group/...e7a1c650?hl=en
    suggests alternate calculations that will be more accurate in certain
    circumstances.

    Jerry

    acjim wrote:

    > Hi,
    >
    > I'm using the "Power" trendline in an XY scatter chart and want to use
    > the formula and the rsquared result in a worksheet.
    >
    > What worksheet function can I use to to show the function (or it's
    > components) and the rsquared within the worksheet?
    >
    > (The formula stated on the chart is: y = 644.691x^-0.895)
    >
    > I've looked at LINEST but that seems to only give a straight line
    > trend?
    >
    > LOGEST gives me the exponential result?
    >
    > Basically I'm worried about using the rsquared value from the chart if
    > I don't have it through a function as well.
    >
    > Anyone able to help?
    >
    > Thanks!



  9. #9
    Jerry W. Lewis
    Guest

    Re: Excel Function to Match Power Trendline in Chart?

    Despite extremely misleading text in Help, LINEST is not limited to
    straight lines; it fits models that are linear in the unknown
    coefficients (polynomials, etc.), cf.
    http://www.stfx.ca/people/bliengme/E...Polynomial.htm
    If y=a*x^b then ln(y)=ln(a)+b*ln(x), which the chart trendline uses to
    estimate the coefficients. In that second form, you can use LINEST, or
    SLOPE, INTERCEPT, and RSQ. If you do not have Excel 2003,
    http://groups-beta.google.com/group/...e7a1c650?hl=en
    suggests alternate calculations that will be more accurate in certain
    circumstances.

    Jerry

    acjim wrote:

    > Hi,
    >
    > I'm using the "Power" trendline in an XY scatter chart and want to use
    > the formula and the rsquared result in a worksheet.
    >
    > What worksheet function can I use to to show the function (or it's
    > components) and the rsquared within the worksheet?
    >
    > (The formula stated on the chart is: y = 644.691x^-0.895)
    >
    > I've looked at LINEST but that seems to only give a straight line
    > trend?
    >
    > LOGEST gives me the exponential result?
    >
    > Basically I'm worried about using the rsquared value from the chart if
    > I don't have it through a function as well.
    >
    > Anyone able to help?
    >
    > Thanks!



  10. #10
    Jerry W. Lewis
    Guest

    Re: Excel Function to Match Power Trendline in Chart?

    Despite extremely misleading text in Help, LINEST is not limited to
    straight lines; it fits models that are linear in the unknown
    coefficients (polynomials, etc.), cf.
    http://www.stfx.ca/people/bliengme/E...Polynomial.htm
    If y=a*x^b then ln(y)=ln(a)+b*ln(x), which the chart trendline uses to
    estimate the coefficients. In that second form, you can use LINEST, or
    SLOPE, INTERCEPT, and RSQ. If you do not have Excel 2003,
    http://groups-beta.google.com/group/...e7a1c650?hl=en
    suggests alternate calculations that will be more accurate in certain
    circumstances.

    Jerry

    acjim wrote:

    > Hi,
    >
    > I'm using the "Power" trendline in an XY scatter chart and want to use
    > the formula and the rsquared result in a worksheet.
    >
    > What worksheet function can I use to to show the function (or it's
    > components) and the rsquared within the worksheet?
    >
    > (The formula stated on the chart is: y = 644.691x^-0.895)
    >
    > I've looked at LINEST but that seems to only give a straight line
    > trend?
    >
    > LOGEST gives me the exponential result?
    >
    > Basically I'm worried about using the rsquared value from the chart if
    > I don't have it through a function as well.
    >
    > Anyone able to help?
    >
    > Thanks!



  11. #11
    Jerry W. Lewis
    Guest

    Re: Excel Function to Match Power Trendline in Chart?

    Despite extremely misleading text in Help, LINEST is not limited to
    straight lines; it fits models that are linear in the unknown
    coefficients (polynomials, etc.), cf.
    http://www.stfx.ca/people/bliengme/E...Polynomial.htm
    If y=a*x^b then ln(y)=ln(a)+b*ln(x), which the chart trendline uses to
    estimate the coefficients. In that second form, you can use LINEST, or
    SLOPE, INTERCEPT, and RSQ. If you do not have Excel 2003,
    http://groups-beta.google.com/group/...e7a1c650?hl=en
    suggests alternate calculations that will be more accurate in certain
    circumstances.

    Jerry

    acjim wrote:

    > Hi,
    >
    > I'm using the "Power" trendline in an XY scatter chart and want to use
    > the formula and the rsquared result in a worksheet.
    >
    > What worksheet function can I use to to show the function (or it's
    > components) and the rsquared within the worksheet?
    >
    > (The formula stated on the chart is: y = 644.691x^-0.895)
    >
    > I've looked at LINEST but that seems to only give a straight line
    > trend?
    >
    > LOGEST gives me the exponential result?
    >
    > Basically I'm worried about using the rsquared value from the chart if
    > I don't have it through a function as well.
    >
    > Anyone able to help?
    >
    > Thanks!



  12. #12
    Jerry W. Lewis
    Guest

    Re: Excel Function to Match Power Trendline in Chart?

    Despite extremely misleading text in Help, LINEST is not limited to
    straight lines; it fits models that are linear in the unknown
    coefficients (polynomials, etc.), cf.
    http://www.stfx.ca/people/bliengme/E...Polynomial.htm
    If y=a*x^b then ln(y)=ln(a)+b*ln(x), which the chart trendline uses to
    estimate the coefficients. In that second form, you can use LINEST, or
    SLOPE, INTERCEPT, and RSQ. If you do not have Excel 2003,
    http://groups-beta.google.com/group/...e7a1c650?hl=en
    suggests alternate calculations that will be more accurate in certain
    circumstances.

    Jerry

    acjim wrote:

    > Hi,
    >
    > I'm using the "Power" trendline in an XY scatter chart and want to use
    > the formula and the rsquared result in a worksheet.
    >
    > What worksheet function can I use to to show the function (or it's
    > components) and the rsquared within the worksheet?
    >
    > (The formula stated on the chart is: y = 644.691x^-0.895)
    >
    > I've looked at LINEST but that seems to only give a straight line
    > trend?
    >
    > LOGEST gives me the exponential result?
    >
    > Basically I'm worried about using the rsquared value from the chart if
    > I don't have it through a function as well.
    >
    > Anyone able to help?
    >
    > Thanks!



  13. #13
    Jerry W. Lewis
    Guest

    Re: Excel Function to Match Power Trendline in Chart?

    Despite extremely misleading text in Help, LINEST is not limited to
    straight lines; it fits models that are linear in the unknown
    coefficients (polynomials, etc.), cf.
    http://www.stfx.ca/people/bliengme/E...Polynomial.htm
    If y=a*x^b then ln(y)=ln(a)+b*ln(x), which the chart trendline uses to
    estimate the coefficients. In that second form, you can use LINEST, or
    SLOPE, INTERCEPT, and RSQ. If you do not have Excel 2003,
    http://groups-beta.google.com/group/...e7a1c650?hl=en
    suggests alternate calculations that will be more accurate in certain
    circumstances.

    Jerry

    acjim wrote:

    > Hi,
    >
    > I'm using the "Power" trendline in an XY scatter chart and want to use
    > the formula and the rsquared result in a worksheet.
    >
    > What worksheet function can I use to to show the function (or it's
    > components) and the rsquared within the worksheet?
    >
    > (The formula stated on the chart is: y = 644.691x^-0.895)
    >
    > I've looked at LINEST but that seems to only give a straight line
    > trend?
    >
    > LOGEST gives me the exponential result?
    >
    > Basically I'm worried about using the rsquared value from the chart if
    > I don't have it through a function as well.
    >
    > Anyone able to help?
    >
    > Thanks!



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