Andrea Calandra <[EMAIL PROTECTED]> writes: > I'm student in biomedical engineer and i have to solve this formula > for immuno-assay. I need to design a calibration curve > > But i don't understand How can i write this formula in R language: > y = a + (c - a) /(1+ e[-b(x-m]) > > where > x = ln(analyte dose + 1) > y = the optical absorbance data > a = the curves top asymptote > b = the slope of the curve > c = the curves bottom asymptote > m = the curve X intercept > > I have to calculate the parameters (a,b,c,m).After with X that i know > i calculate the Y.
You have asked essentially the same question three or four times and have gotten the same answer each time. You tell us IN ALL CAPS that you are doing five-point interpolation and we point out that you have only four parameters in that formula. Asking the same question over and over and over again will not change that. Perhaps you should accept the fact that you cannot interpolate five points with a four-parameter model then reconsider your question. If you wish to do a least-squares fit of those parameters you can use nls and SSfpl as I suggested in an earlier response. ______________________________________________ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help