search for: drc

Dear all, I can use the very nice drc package (multdrc()) to model and plot a dataframe containing dose and response values. I can also use predict.drc() to yield response values given a dose. I need to do the opposite, estimate a dose given the response. The general predict documentation seems to say that this is possible, but...

Dear R Community, I am using the package DRC ( to fit a boltzman model to my data. I can fit the model and extract the lower limit, upper limit, and ED50 (aka V50), but I cannot figure out how to get the slope of the curve at ED50. Is there a simple way to do this? I've searched the mailing list and looked through the package documenta...

Hi, I am trying to use drc package to calculate IC50 value. The ED50 calculated in some models (LL4 for example) as a response half-way between the upper and lower limit, which is the definition of the relative IC50 value. Does that mean the ED50 in drc package is IC50? How the ED function in drc package distinguish to estim...

Hello, We use drc to fit dose-response curves, recently we discovered that there are quite different standard error values returned for the same dataset depending on the drc-version / R-version that was used (not clear which factor is important) On R 2.9.0 using drc_1.6-3 we get an IC50 of 1.27447 and a standard err...

R-helpers, I am using the package "drc" to fit a 4 parameter logistic model. When I use the predict function to get prediction on a new dataset, I am not getting the requested confidence or prediction intervals. Any idea what is going on? Here is code to reproduce the problem: --- library(drc) # Fit model to existing datas...

I have dose response data I have analyzed with the 'drc' package. Using plot() works great. I want to arrange my plots and source data on a single page. I think 'gridExtra' is the usual package for this. I could use plot() and par(mfrow=...), but then I can't put the source data table on the page. gridExtra provides grid.table() whic...

On Fri, 18 May 2018, Ed Siefker wrote: > I have dose response data I have analyzed with the 'drc' package. > Using plot() works great. I want to arrange my plots and source > data on a single page. I think 'gridExtra' is the usual package for > this. > > I could use plot() and par(mfrow=...), but then I can't put the source > data table on the page. > &gt...

Quiero comparar varias dosis letales 50% (LD50) usando análisis probit. He seguido un ejemplo que viene en paquete DRC, pero no obtengo el resultado esperado. Lo que quiero es saber si las LD50s, son diferentes y si la diferencias son estadísticamente significativas. Gracias de antemano. José Arturo e-mail. jafarfan@uady.mx <grejon@uady.mx> e-mail alterno. jafarfan@gmail.com <julian.garcia.rejon@gmail...

Hi! I want to use the DRC package in order to calculate the IC50 value of an enzyme inhibition assay. The problem is that the estimated ED50, is always out of the fitted curve. In the example below, I had a ED50 value of 2.2896, But when I predict the response level for this concentration I get a value of 45.71 instead o...

Dear R users, I'm a little lost on how to define pmodels for the DRC package. My goals are to produce isoboles of binary toxicity data. any tips? I really just need to know what pmodels refers to. Cheers, Pat -- View this message in context: http://r.789695.n4.nabble.com/pmodels-in-DRC-tp4190567p4190567.html Sent from the R help mailing list archive at Nabble....

...On the command R window I define - Ignored: > x=c(12,24,13,11,23,10,9,17,11,14,18) > y=c(10,11,9,8,5,12,11,21,12,13,14) then I load the press source code, I run it using the x and y values defined before and I get the following > press(x,y) Loading required package: drc Loading required package: alr3 Loading required package: lattice Loading required package: magic Loading required package: abind Loading required package: MASS Loading required package: nlme Loading required package: plotrix 'drc' has been loaded. Please cite R and '...

R-helpers, I recently submitted a help request for the predict.drm function found in the drc package. I am still having issues with the function and I am submitting reproducible code hoping that somebody can help me figure out what is going on. -------- library(drc) # Fit a 4 parameter logistic model to ryegrass dataset fit <- drm(rootl ~ conc, data = ryegrass, fct = LL.4()) summary(...

Hi every one, I am using the package 'drc' to model root elongation using dose response data. I don't know which model I should use. Though I don't know which model I should use, I tried the following codes given below. But it produced the error messages.Can any one tell me the code in 'drc' package to find out the EC (...

Hi, I am currently trying to do dose-response curves using weighted 4-parameter model (4PL). The weighting was based on 1/(expected variance) derived from historical data. I tried both drm() from drc package, and nls(), found very different results derived from drm() vs. nls() using "weights=" argument. d1<-read.table("d1.txt",sep='\t',header=T,row.names=1) drm(y~x,weights=1/exp((-1.8286)+0.05481*y-0.000405225*(y-48.34177)^2),data = d1,fct = LL.4(),control=drmc...

Hi, the following R lines work fine in R 2.4.0 alpha (and older R versions), but not in R 2.4.0 beta (details below): library(drc) # to load the dataset 'PestSci' library(nlme) ## Starting values sv <- c(0.328919, 1.956121, 0.097547, 1.642436, 0.208924) ## No error m1 <- nlme(SLOPE ~ c + (d-c)/(1+exp(b*(log(DOSE)-log(e)))), fixed = list(b+c+d+e~1),...

Hello, I am trying to fit my Elisa results (absorbance readings) to a standard curve. To create the standard curve model, I performed a 4-parameter logistic fit using the 'drc' package (ExpectedConc~Absorbance). This gave me the following: > FourP A 'drc' model. Call: drm(formula = Response ~ Expected, data = SC, fct = LL.4()) Coefficients: b:(Intercept) c:(Intercept) d:(Intercept) e:(Intercept) 1.336 6.236 85.521 59....

Buenos dias R-help-es, Estoy interesado en estimar una curva dosis-respuesta para un conjunto de datos y para ello, estoy utilizando la libreria "drm". Hasta ahi todo bien. Me gustaria automatizar algunas cosas y el primer paso para ello es la estimacion del modelo. Si la estimacion funciona, todo lo demas funciona; de lo contrario, todo fallara. Tengo algunas lineas que mitigan un

Hi, the following R lines work fine in R 2.4.0, but not in R 2.4.1 or any devel versions of R 2.5.0 (see below for details). library(drc) # to load the dataset 'PestSci' library(nlme) ## Setting starting values sv <- c(0.43355869, 2.49963220, 0.05861799, 1.73290589, 0.38153146, 0.24316978) ## No error m1 <- nlme(SLOPE ~ c + (d-c)/(1+exp(b*(log(DOSE)-log(e)))), fixed = list(b+c+d+e~1), random = d~1|CURVE, start =...

...Jul 30 18:53:02 localhost_10 kernel: nfs: server 10.147.4.99 not responding, still trying 10721 18:53:28.873 /var/log/messages: Jul 30 18:53:02 localhost_10 kernel: nfs: server 10.147.4.99 not responding, still trying Here is the error message in nfs.log for gluster: 19:26:18.440498] I [rpc-drc.c:689:rpcsvc_drc_init] 0-rpc-service: DRC is turned OFF [2017-07-30 19:26:18.450180] I [glusterfsd-mgmt.c:1620:mgmt_getspec_cbk] 0-glusterfs: No change in volfile, continuing [2017-07-30 19:26:18.493551] I [glusterfsd-mgmt.c:1620:mgmt_getspec_cbk] 0-glusterfs: No change in volfile, continuing [2...

...r/local/share/Staff/SSS > writeable = yes > inherit permissions = yes > > [JMC] > comment = JMC Global Share > path = /usr/local/share/Staff/JMC > writeable = yes > write list = @staff > read list = @staff > > [DRC] > comment = DRC > path = /usr/local/share/Staff/DRC > writeable = yes > inherit permissions = yes > > [CLA] > comment = CLA > path = /usr/local/share/Staff/CLA > writeable = yes > inherit permissions = ye...