On Mar 23, 2011, at 10:05 AM, agent dunham wrote:
Dear all,
I've fitted a lm using 61 data (training data), and I'left 10 as
test data.
Training data and test data are stored in an excell.
training <- read.xls("C:/...../training.xls") , the same for test.
That is:
v1
v2
...
v15
When I type str(training) and str(test), both sets have the same names
The resulting model is lms <- lm(vd ~ log(v1) + fv2+ fv5+ fv7 ) -
fvi means
they were turned into factors-
plms<- predict(lms, new=test ,interval="prediction")
Error at model.frame.default(Terms, newdata, na.action = na.action,
xlev =
object$xlevels) :
length of the variables are different (found for 'fv2')
More: Warning messages lost
'newdata' had 10 rows but variable(s) found have 61 rows
q1: What does it mean?
In the absence of a reproducible example it is difficult to say.
q2: Do I have to change test data names, so they have the same as the
resulting lm?
At a minimum, that would be required. Read help(predict.lm) and pay
particular attention to _all_ the details mentioned in the newdata
section.
q3: Do I have to do anything special because of the log
transformation?
No.
q4: Afterwards I'd like to plot it, is this way?: plot(plms)
Specify what kind of plot. You are likely to be surprised and perhaps
disappointed if you use the default plot method for lm objects.
As the standard postscript says:
and provide commented, minimal, self-contained, reproducible code.
--
David Winsemius, MD
West Hartford, CT
______________________________________________
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
