Re: [R] Non linear regression - Von Bertalanffy Growth Function - "singular gradient matrix at initial parameter estimates"

? Is there an R function to do that? Best, Xochitl C. <>< <>< <>< <>< Xochitl CORMON +33 (0)3 21 99 56 84 Doctorante en écologie marine et science halieutique PhD student in marine ecology and fishery science <>< <>< <>< <>

[R] Non linear regression - Von Bertalanffy Growth Function - "singular gradient matrix at initial parameter estimates"

stand properly yet). If I give a starting value for a and b only, I have an error message stating "step factor below minFactor" (even when minFactor is set to 1000). Any help will be more than welcome as this is quite urgent Best, Xochitl C. -- <>< <

[R] Problem running stepAIC within a function.

need afterwards to assign this object to the global environment. See ?assign Maybe that can help some people. -- <>< <>< <>< <>< Xochitl CORMON +33 (0)3 21 99 56 84 Doctorante en écologie marine et science halieutique PhD student in marine ecology and fishe

Re: [R] Prediction of response after glm on whitened data

are indeed pretty similar. So if someone knows a function which allows me to predict my response and its associated variance using R after whitening and glm (see original question), I am still eager to know it. Best, Xo <>< <>< <>< <>< Xochitl CORMON

[R] Prediction of response after glm on whitened data

(NPw_i - rho * NPw_i-1) + epsilon with mu being the intercept, beta the regression coefficient and epsilon the error, ? Thank you for your help, Best, Xochitl C. -- <>< <>< <>< <>< Xochitl CORMON +33 (0)3 21 99 56 84 Doctorante en écologie marine et scien

Re: [R] glm's for a logistic regression - no warnings?

e the number of step if you see nothing but in my opinion 30 steps are enough. There is several packages to handle separated data, brglm and logistf are the two I recall. Good luck! Xochitl C. On Tue, Oct 1, 2013 at 11:34 AM, Xochitl CORMON mailto:xochitl.cor...@ifremer.fr>

Re: [R] glm's for a logistic regression - no warnings?

<>< <>< <>< <>< Xochitl CORMON Le 01/10/2013 17:29, Dimitri Liakhovitski a écrit : Thank you very much, Bert - it's very helpful. This post says that R issues a warning: Warning message: *glm.fit: fitted probabilities numerically 0 or 1 occurred *

Re: [R] glm's for a logistic regression - no warnings?

Hi, I did have warning messages about convergence issues using binomial GLM with logit link with my data in the past Do you detect separation using the function separation.detection{brglm}? Regards, Xochitl C. <>< <>< <>< <>< Xochitl CORMON

Re: [R] Stepwise selection with qAIC and qBIC

l1, model2, model3, model4, model5, model6, dispersion = disp, type = "qAIC", base = TRUE) # we use the global dispersion parameter as recommended in Burnham & Anderson, 2002 <>< <>< <>< <>< Xochitl CORMON +33 (0)3 21 99 56 84 Doctorante en s

[R] Stepwise selection with qAIC and qBIC

the selection using this criterion and having the dispersion parameter, customizing stepAIC function for example? Unfortunately I am reaching here my abilities in statistics and programming and cannot figure out if what I want to do is doable or not. Thank you for your help, Regards, Xochitl

Re: [R] Naming columns

ch one is "V1" (TRUE) and attributing to this column the new name "Toto". You can also use the the number of column but even if it seems simpler it is not recommended as you can get problem if the column order is changed. Code to change 1st column name: colnames(dataset)[1]

Re: [R] transform variables

also use as already suggested reshape function. Note the syntax is slightly different. ?reshape Good luck, Xochitl C. <>< <>< <>< <>< Xochitl CORMON +33 (0)3 21 99 56 84 Doctorante en sciences halieutiques PhD student in fishery sciences <>< <&

Re: [R] sample {base}

e size of the data or 5. Sarah On Wed, Jun 5, 2013 at 10:27 AM, Xochitl CORMON wrote: Hi all, I'm trying to randomly select sample numbers for length class groups (5 per length class). For this I'm using a loop FOR and the function sample () and specified a size for the sampling

[R] sample {base}

t;50_59", "60_69", "70_") SpCode <- list ("POLLVIR ", "MERLMER") a <- as.character(sample(Gpool$SampleNb[Gpool$LngtClas == LngtClas[[4]] & Gpool$SpCode == SpCode[[2]]], size = 5, replace = FALSE)) You can find enclosed my dataset, Thank yo

Re: [R] Loop FOR with histogram() from lattice

uot;count", col = "lightgrey", xlab= "LngtClas", main = paste("Length distribution per species for Mpool", "2", sep = "_"))) Sent from my iPad On Jun 5, 2013, at 4:37, Xochitl CORMON wrote: Hi all, I'm encountering a problem I do not und

[R] Loop FOR with histogram() from lattice

p I obtained windows filled grey (no plot drawn at all) but the print (i) print a "2" as expected. I really dont understand what's wrong with the loop. There is no error message and no notification in R. You can find enclosed my data in txt file. Thank you very much for an

Re: [R] Separation issue in binary response models - glm, brglm, logistf

Le 28/02/2013 17:22, Ben Bolker a écrit : Thank you for your help ! Xochitl CORMON ifremer.fr> writes: Dear all, I am encountering some issues with my data and need some help. I am trying to run glm analysis with a presence/absence variable as response variable and several explanat

[R] Separation issue in binary response models - glm, brglm, logistf

ial, data = CPUE_table) --- -- <>< <>< <>< <>< Xochitl CORMON +33 (0)3 21 99 56 84 Doctorante en sciences halieutiques PhD student in fishery sciences <>< <>< <>