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Hello! I have a dataset with monthly temperatures for 4 different years and I would like to test if they are significantly different between the years. As I collected the data for different sites I wondered if there were some possibility to perform the calculation at once or if I have to repeat it for each site. I tried like this: Model_Temp <- lmer(Temp ~Year +

Hello! When I am analyzing proportion data, I usually apply logistic regression using a glm model with binomial family. For example: m <- glm( cbind("not realized", "realized") ~ v1 + v2 , family="binomial") However, sometimes I don't have the number of cases (realized, not realized), but only the proportion and thus cannot compute the binomial model. I just

Hello, I plot the abundance of a species in relation to the date. To have the date as a continous variable I put it in the format "standard" in excel (f.ex. 39939 means 06.05.2009). R uses 39939 on the x axis, but I would like to have "06.05". I tried to use as.Date as suggested in some discussion but I don't manage to use it, the returned date is not correct. Do you have

Hello! It is not really linked to R, but can somebody explain me why we sometimes make a mantel test directly for to distance matrices and sometimes we first make a gradient analysis and then a mantel test between the axis? Thank you -- View this message in context: http://www.nabble.com/Mantel-test-tp25439984p25439984.html Sent from the R help mailing list archive at Nabble.com.

Hello! I would like to make a scatterplot of my data, but the problem is that several points have the same x and y values and are represented as only one point. I wonder if there is a way to represent the data points, but with point size representing the frequency of the depicted x-y value? Thank you! -- View this message in context:

Hello, I have a matrix of species abundance with a lot of 0 values. I would like to plot the species abundance vs date, but I don't want that the 0 values appear as points on my graph. Do you know how I could represent only non-0 values? Thank you very much -- View this message in context: http://www.nabble.com/Exclude-0-values-from-plot-tp25235290p25235290.html Sent from the R help mailing

Hello, I performed a Mantel test and plotted communitiy similarities. I would like to add a least square line. I thought about using abline taking as slope the r-statistic of the Mantel test and calculating the y-intercept analytically. Is this method correct? Is there any function for this calculation? Thank you -- View this message in context:

Hello, I read a lot about ordination, but I am still confused... I have data on species presence/absence for 8 different sites and I would like to represent my species and the sites on an ordination plot to see if some species are associated with specific sites. I used metaMDS function, which displays both sites and species and it seems to work well. However why are most people using CA instead of

Hello, I would like to plot a large number of graphs (43) in a same window. I tried wit par(mfrow=c(8,5)), but when I give the code for the plots I receive a error message saying that the margins are to wide. Can someone help me? Is it possible to put so many graphs in a single window? Thank you -- View this message in context:

Hello, I am trying to do contrasts after applying a binomial mixed effect model with the function lmer. I have to extract the fix effect values, but as I write fixef(model), I get this error message: Error in UseMethod("fixef") : no method for 'fixef' with objects of class "mer" Has anybody some ideas why? And how can I then post-hoc testing my data if I cannot do

Hello! I am trying to model data on species abundance (count data) with a poisson error distribution. I have a fixed and a random variables and thus needs a mixed model. I strongly doubt that my model is overdispersed but I don't know how to get the overdispersion parameter in a mixed model. Maybe someone can help me on this point. Secondly, it seems that quasi models cannot be implemented