meaning of glm(value ~ .,
All of your points are accepted, and I also give you credit for reading the "formula" page better than I.
On Jun 19, 2009, at 10:08 AM, Gavin Simpson wrote:
On Fri, 2009-06-19 at 09:24 -0400, David Winsemius wrote:
On Jun 19, 2009, at 9:00 AM, onyourmark wrote:
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means and also, I see data=crs$dataset[,c(1:59,922)] I have read that the data argument is optional here "an optional data frame, list or environment (or object coercible by as.data.frame to a data frame) containing the variables in the model. If not found in data, the variables are taken from environment(formula), typically the environment from which glm is called" when they say "data", is that meant to include the dependent variable as well.
Yes.
It has to be defined in 'data' or the environment of 'formula', so it depends on what the OP meant by "meant to include". You can include it in 'data' but don't have to.
In other words, in the above statement 'value' is the dependent variable and it is also column 922 in the data set. Is this correct?
Yes.
No - you can't say that it is variable 922, or even any of 1:59 or 922 for the reasons mentioned above. set.seed(123) dat <- data.frame(A = rnorm(100), B = rnorm(100), C = rnorm(100)) Y <- rpois(100, 2) mod <- glm(Y ~ ., data = dat[,c(1,3)], family = poisson) mod If all you have is this: mod <- glm(Y ~ ., data = dat[,c(1,3)], family = poisson) You can't say anything more about Y than that it is either in 'dat' or in the environment of 'formula ', which in this case is the global workspace. G
David Winsemius, MD Heritage Laboratories West Hartford, CT