Recent content by dwwhite5150

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    Sigma Plot, Non-linear regression, fitting a line to a set of points

    Rollingstein, That's pretty awesome, still can't get sigmaplot to accept the equations as fitting constraints. also I have to make the equations dynamic because p1, p2, p3, p4, OP(x,y), m(OP) change for every subject. OP is the operating point for which I have the point and slope. I have...
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    Sigma Plot, Non-linear regression, fitting a line to a set of points

    rollingstein, thanks for the reply. I tried putting the solution that you gave as a constraint but i got an error message. I am assuming that it is a parenthetical problem so i put it into excel and the slope I get back while putting in the parameters 1.6*10^-74. It is probably something...
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    Sigma Plot, Non-linear regression, fitting a line to a set of points

    DrDu, You are probably correct in the assumption that I cannot visualize the solution you have given in my mind. Mathematically you suggestions are probably spot on and I will search the SigmaPlot manuals for Lagrangian multipliers and I will also try to eliminate a variable in the equation...
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    Sigma Plot, Non-linear regression, fitting a line to a set of points

    DrDu, thank you for the reply, I guess what I am really asking is, "In SigmaPlot, Does anybody know how to force an inverse logistic function curve through a known point at a known slope, while fitting the the curve?" the reason I ask is that through manipulation of blood pressure, I get a...
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    Sigma Plot, Non-linear regression, fitting a line to a set of points

    I model arterial baroreflex data that I have collected in humans using the Kent equation which is: y=p1/(1+exp((x-p3)*p2))+p4; where Y=heart rate, X= estimated carotid sinus pressure, p1=range of Y, p2=slope coeff, p3=centerpoint on X, p4 = minimum Y. I use Sigma Plot to do a best fit line...
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