Dear all I need to obtain an estimate of the 50% lethal dose (LD50) from a logistic regression model obtained by applying the glm procedure to some binomial data. The model appears to fit the data very well. I used dope.p from MASS to try and find LD50. The following output appears:> dose.p(iso.glm.logit, cf = c(1,3), p = 1:3/4)Error in dose.p(iso.glm.logit, cf = c(1, 3), p = 1:3/4) : subscript out of bounds What is the problem here? The error disappears when fiddle around with cf (e.g., cf = c(1,2)), but I have no idea what this does, or even what the cf parameter is used for. Any help appreciated. Kind regards, Albertus Dr. Albertus J. Smit Department of Botany University of Cape Town Private Bag Rondebosch 7700 South Africa Tel. +27 21 689 3032 -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html Send "info", "help", or "[un]subscribe" (in the "body", not the subject !) To: r-help-request at stat.math.ethz.ch _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._
Hi R expert users: I want to know if any body is working or have some functions to apply times series disaggregation. Thank you very much for your help Kenneth -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html Send "info", "help", or "[un]subscribe" (in the "body", not the subject !) To: r-help-request at stat.math.ethz.ch _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._
On Tue, 16 Jul 2002, Smit, A, Albertus, Dr wrote:> Dear all > > I need to obtain an estimate of the 50% lethal dose (LD50) from a > logistic regression model obtained by applying the glm procedure to > some binomial data. The model appears to fit the data very well. I > used dope.p from MASS to try and find LD50. > > The following output appears: > > > dose.p(iso.glm.logit, cf = c(1,3), p = 1:3/4) > Error in dose.p(iso.glm.logit, cf = c(1, 3), p = 1:3/4) : > subscript out of bounds > > What is the problem here? The error disappears when fiddle around > with cf (e.g., cf = c(1,2)), but I have no idea what this does, or even > what the cf parameter is used for.There is a help page for dose.p(), and it does explain the argument `cf'! Probably the default cf=1:2 is what you want, but without seeing how you created iso.glm.logit we can only guess. -- Brian D. Ripley, ripley at stats.ox.ac.uk Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/ University of Oxford, Tel: +44 1865 272861 (self) 1 South Parks Road, +44 1865 272860 (secr) Oxford OX1 3TG, UK Fax: +44 1865 272595 -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html Send "info", "help", or "[un]subscribe" (in the "body", not the subject !) To: r-help-request at stat.math.ethz.ch _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._
At 12:40 PM 7/16/2002 +0200, Smit, A, Albertus, Dr wrote:>I need to obtain an estimate of the 50% lethal dose (LD50) from a >logistic regression model obtained by applying the glm procedure to >some binomial data. The model appears to fit the data very well. I >used dope.p from MASS to try and find LD50. > >The following output appears: > > > dose.p(iso.glm.logit, cf = c(1,3), p = 1:3/4) >Error in dose.p(iso.glm.logit, cf = c(1, 3), p = 1:3/4) : > subscript out of bounds > >What is the problem here? The error disappears when fiddle around >with cf (e.g., cf = c(1,2)), but I have no idea what this does, or even >what the cf parameter is used for. > >Any help appreciated.Dear Albertus, From the help page for dose.p: cf The terms in the coefficient vector giving the intercept and coefficient of (log-)dose Apparently, your model (unlike the example on the help page) has only one predictor, presumably the log dose; there are, therefore, only two coefficients -- for the intercept and log dose. I hope that this helps, John ----------------------------------------------------- John Fox Department of Sociology McMaster University Hamilton, Ontario, Canada L8S 4M4 email: jfox at mcmaster.ca phone: 905-525-9140x23604 web: www.socsci.mcmaster.ca/jfox ----------------------------------------------------- -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html Send "info", "help", or "[un]subscribe" (in the "body", not the subject !) To: r-help-request at stat.math.ethz.ch _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._