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#1
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cubic regression with no quadratic term
how do i do cubic regression without the quadratic term? how do i tell excel
there is no x^2? i just want it to be ax^3+bx+c |
#2
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Cyanlce wrote:
how do i do cubic regression without the quadratic term? how do i tell excel there is no x^2? i just want it to be ax^3+bx+c I presume you have a column of X and a column of Y data. Add a third column which is your scoring function that you want to minimize. Conventionally that would be something like { } = (Y - YourF(x))^2 At the bottom of that column you sum up all your error function values. Then you just use Solver to optimize the a, b, c values that you've used in your scoring function equation to minimize the sum of your error function values. Good luck... Bill |
#3
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Assuming that yData and xData are columnar data with no empty or
non-numeric cells, then select 3 contiguous cells in a row and array enter (Ctrl-Shift-Enter) =LINEST(yData,xData^{1,3}) As documented by Help, the reculting coeffients will be (cubic, linear, intercept) which is the opposite order to what you might expect. Jerry Cyanlce wrote: how do i do cubic regression without the quadratic term? how do i tell excel there is no x^2? i just want it to be ax^3+bx+c |
#4
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thanks
"Cyanlce" wrote: how do i do cubic regression without the quadratic term? how do i tell excel there is no x^2? i just want it to be ax^3+bx+c |
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