[R] Ordinal logistic regression (lrm)- checking model assumptions

2011-02-11 Thread Anna Berthinussen
Dear all, I have been using the lrm function in R to run an ordinal logistic regression and I am a bit confused about the methods for checking the model assumptions. I have produced residual plots in R of the score.binary type which I think look ok. However, the partial type plots show

[R] GEE - order of data?

2011-01-31 Thread Anna Berthinussen
Dear all, I am trying to do a GEE on count data and I am having problems with how to order the data. Below is a simplified example of what my data looks like.. Route Time Day Pass Distance 130 1 40 160 1 12 200 1 120

[R] Modifying effect display (effects package)

2010-12-20 Thread Anna Berthinussen
Hi, I am using the effects package and plot() to produce an effect plot for a higher order term from a GLM. However, I need to modify the graph it produces by removing the tick marks and axes from the right and top of the graph, and moving the remaining tick marks inside the axes. Does

[R] Colour points in plot according to third variable

2010-07-29 Thread Anna Berthinussen
Hi, I am using the plot function to make a simple plot of my data with one variable against another and want to colour the data points according to a third variable. The third variable is continuous (Time) and I want to try two different ways of colouring the data points, either: Divide

[R] Interpreting NB GLM output - effect sizes?

2010-07-06 Thread Anna Berthinussen
Hi, I am trying to find out how to interpret the summary output from a neg bin GLM? I have 3 significant variables and I can see whether they have a positive or negative effect, but I can't work out how to calculate the magnitude of the effect on the mean of the dependent variable. I used a log