On 03/03/2011 01:13 AM, Laura Clasemann wrote:
Hi,
I have a table in R with data I needed and need to create a contingency table
out of it. The table I have so far looks like this:
Binger
r
DietType No Yes
Dangerous 15 12
Healthy 52 9
None 134 24
Unhealthy 72 23
These are the error messages that I keep getting whenever I try to get a
contingency table. I'm not sure why it won't work for me, any help would be
appreciated!
nametable<-table(excat,recat)
Error in table(excat, recat) : object 'excat' not found
Hi Laura,
The above looks like a contingency table, but I suspect that it is in a
format that is not recognized as such by R. If I read in the above, less
the top two lines ("Binger" and "r"), I get a data frame.
lc.df<-read.table("lc.dat",header=TRUE)
lc.df
DietType No Yes
1 Dangerous 15 12
2 Healthy 52 9
3 None 134 24
4 Unhealthy 72 23
If I then try to run a chi-square test on the numeric columns of the
data frame,
chisq.test(lc.df[,2:3])
Pearson's Chi-squared test
data: lc.df[, 2:3]
X-squared = 14.5011, df = 3, p-value = 0.002297
I get the expected result. If the table in your message is something
like a table in a word processing document or a text file, R doesn't
know what it is. If it is indeed an R object (which I doubt) it probably
isn't named "excat" (or "recat" for that matter). That may be what is
causing the error message.
A final point is that you probably want your table arranged in order of
the presumed healthiness of the diet, i.e.
Healthy
None
Unhealthy
Dangerous
because I think you are trying to discover whether bingers are more
likely to report less healthy diets.
Jim
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