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Questions tagged [drc]

Analysis of Dose-Response Curves.

Analysis of dose-response data is made available through a suite of flexible and versatile model fitting and after-fitting functions.

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Discrepancies between geom_smooth fit and predict.drc output in R

I am trying to plot dose-response curves using the drc package using the reduced log-normal fit (LN.2), which should be equivalent to the probit dose-response model. When I use the 'predict' function for both the glm package derived probit model…
Gaston d.
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I have a the following message "'collapse' argument should be a formula" while using mixture function (drc package)

While using drc package for mixture prediction on microalgae growth inhibition data, specifically the mixture function, I receive an error message "'collapse' argument should be a formula" , which I don't really understand. I'm using almost exactly…
tciccia
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package drc LL.3

I would like to access the code of the three-parameter log-logistic function in the drc package I know that there is a whole repository on GitHub drc but I can't figure out which script in it describes action of function LL.3. I apologize if my…
user20378754
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The ED50 value differs in drc when calculated vs. plotted

I have a dose-response curve and I need to calculate and plot a 4-parameter logistic regression using the R package drc and ggplot. It needs to have 1 as the upper limit and 0 as the lower limit. It works fine exept that the calculated ED50 value is…
Cookie
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ED50 in non linear logistic regression in R

I am new to R and I want to find the ED50 with its confidence interval in the drc package in R. I found the best model is lorentz.4 according to AIC. But I get a warning message for the confidence interval, plus during the summary. Warning message:…
Satomi
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ELISA in R: how to use curve-specific estimates when applying the ED function to a drc obejct?

Assume that we would like to estimate the concentrations of 2000 samples (500 individuals with 4 samples each) from their observed absorptions. The relationship between absorption and concentration is derived by observing the absorptions of some…
andrjens
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How to fit a Biphasic Dose Response Curve using R?

I am trying to process NanoBRET assay data to analyze competition between Ternary Complex (TC) formation and binary binding between Chimeric Targeted Molecule and weaker affinity interacting species using R. I could not locate the correct library…
RanonKahn
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simple curve fitting in R

I am trying to find a fit for my data. But so far had no luck. Tried the logarithmic, different ones from the drc package .. but I am sure there must be a better one I just don't know the type. On a different note - I would be grateful for advice on…
SunWuKung
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Modeling multiple drm model in drc

I have trouble plotting multiple model drm in the R package DRC. My data comprises of three variables; Doses; Herbicide (Trt) and Timing The dose response curve works fine when I plot Dose and Trt, but when I add Timing I am getting this error:…
Pershang
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drm() Error Convergence failed for some data but not for similar?

I'm trying to loop over some dose-dependent data and fit it using the drm() function. However, for some of the data I get the following error: Error in optim(startVec, opfct, hessian = TRUE, method = optMethod, control = list(maxit = maxIt, …
Norruas
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Plot several fitted curves on one plot with drm function

I'm trying to plot some data that has been fitted with the drm() function from the drc package in R. I want to have several curves in the same plot overlapping each other. I can get one fitted curve and the rest un-fitted into one curve like…
Norruas
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inflection point for 3-parameter weibull in R?

The drc package in R contains self-starting functions to fit a 3-parameter Weibull model to data. The package gives 2 parameterizations of the 3-parameter weibull (https://cran.r-project.org/web/packages/drc/drc.pdf): f(x) = 0 + (d − 0) exp(−…
TKraft
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Error in plotting dose-response curve in ggplot with drc package

I'm getting a half plotted graph when trying to plot the dose-response curve using ggplot in drc package. I'm trying to follow procedure given in a suplementary information from a recent paper on dose response curve. Here is my raw data Please help…
Omi
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Why is my data generating 'Argument is of length zero' in 'dr4pl' dose-response curves?

I am plotting 4 parameter logistic curves. It's a huge dataset with lots of curves, and one of my outputs is failing because the model fit doesn't work for some of the data. Some of the data fails to produce a curve and gives a Warning message:…
OJH
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(in R) How to incorporate dose response IC50 values, from dr4pl models into a ggplot2 curve?

I was helped on this site in combining the dr4pl (the replacement for '''drc''') 4 parameter logistic dose response model with ggplot. It works really well, but I'm looking to incorporate the the IC50 for each curve into the plots, AND to output a…
OJH
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