[R] possum sleeping: thanks and fisher.test() FEXACT error

[Robin Hankin]

Dear helplist

Many many thanks to everyone who helped me.  The trick was to use
tabulate() or, better,

tab <- rep(0,50)
names(tab) <- 1:50
tab[names(table(sleeps))] <- table(c)

My original dataset was a list of 50 trees and a length 12 vector
recording which tree a certain possum slept in on 12 nights.  As
Professor Ripley points out, a Monte-Carlo simulation is easy to set
up, and it shows that chi-squared is inapplicable.

If H0 is that the animal chooses randomly from amongst these 50 trees
then the number of sleeps in each tree is multinomial with n=50 and
p_i=12/50 for i=1:50 (H0 is biologically reasonable: the 50 trees
were those in which a possum slept on at least one occasion).

The next step is to check whether the five animals have different
preferences.  I have an array called alldata which has 50 rows (one
per tree) and five columns (one per animal).

But, in R-1.5.0,

R> fisher.test(alldata[,2:5])
Error in fisher.test(alldata[, 2:5]) : FEXACT error 30.
Stack length exceeded in f3xact.
This problem should not occur. 

what am I doing wrong here?

R> dput (alldata)
structure(c(0, 0, 0, 0, 0, 2, 0, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 
0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 1, 0, 2, 0, 0, 0, 1, 0, 
0, 0, 1, 0, 0, 1, 0, 0, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 3, 0, 1, 
0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 2, 0, 0, 0, 1, 0, 0, 
0, 1, 0, 1, 0, 4, 0, 2, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 
1, 0, 0, 2, 0, 0, 0, 2, 2, 0, 1, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 
0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 2, 0, 0, 0, 3, 0, 0, 0, 0, 
0, 1, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 
1, 0, 0, 0, 0, 2, 0, 0, 0, 0, 8, 0, 0, 0, 3, 0, 0, 0, 0, 0, 0, 
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 0, 
0, 0, 0, 0, 2, 0, 0, 1, 0, 0, 2, 0, 0, 0, 0, 2, 0, 0, 1, 3, 0, 
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 4, 0, 0, 
0, 0), .Dim = c(50, 5), .Dimnames = list(NULL, c("x14", "x88", 
"x82", "x90", "x98")))






-- 

Robin Hankin, Lecturer,
School of Geographical and Environmental Science
Private Bag 92019 Auckland
New Zealand

r.hankin at auckland.ac.nz
tel 0064-9-373-7599 x6820; FAX 0064-9-373-7042

as of: Thu Jun 13 16:19:00 NZST 2002
This (linux) system up continuously for:  287 days, 23 hours, 01 minutes
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