On Oct 8, 2010, at 1:09 PM, Alison Callahan wrote:
See below.
On Fri, Oct 8, 2010 at 1:01 PM, David Winsemius <dwinsem...@comcast.net
> wrote:
On Oct 8, 2010, at 12:46 PM, Alison Callahan wrote:
Hello all,
I am trying to perform an ANOVA on some data in a data frame, but
when
I try to use lm(), I get the following error:
The question that should have been posed was how did you use lm()?
It could be that the inappropriate use of a factor as a dependent
variable was the cause. Did you use something like:
lm(island_id ~ refseq_better, data=dfrm) # ??
Example:
> dfrm <- data.frame(a=factor(rnorm(10)), b=rnorm(10))
> lm(a ~ b, data=dfrm)
Error in storage.mode(y) <- "double" :
invalid to change the storage mode of a factor
In addition: Warning message:
In model.response(mf, "numeric") :
using type="numeric" with a factor response will be ignored
Error in storage.mode(y) <- "double" :
invalid to change the storage mode of a factor
In addition: Warning message:
In model.response(mf, "numeric") :
using type="numeric" with a factor response will be ignored
Here is a subset of my data:
island_id refseq_better total refseq_proportion
fiveprime threeprime island_size
1a 29 57 0.508771929824561
11127 201378 190251
1c 27 90 0.3
6303879 6600994 297115
1d 33 115 0.28695652173913
7001283 7421591 420308
2b 11 42 0.261904761904762
4381375 4520137 138762
2d 27 81 0.333333333333333
5203929 5497271 293342
3a 44 141 0.312056737588652
28792 552044 523252
When I use sapply(dataframe,mode) to check the modes of the columns,
this is my output:
island_id refseq_better total
refseq_proportion
"numeric" "numeric" "numeric"
"numeric"
fiveprime threeprime island_size
"numeric" "numeric" "numeric"
So?
mode(factor(1:10))
[1] "numeric"
Storage mode is not the right question. "class" is the correct
question.
Best would be to try is.factor()
Looking at the error message, the problem does appear to be with
storage mode ... is this affected by whether the variables are
factors? Note this part of the error:
Error in storage.mode(y) <- "double" :
invalid to change the storage mode of a factor
How do I need to change the format of my data frame so that I do not
get the above error?
Figure out which of your columns are factors and apply the FAQ 7.12
--
David.
Thanks!
Alison Callahan
PhD candidate
David Winsemius, MD
West Hartford, CT
Thanks,
Alison
David Winsemius, MD
West Hartford, CT
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