Thank you Chuck,
Here is the head of my data set (tjornres):
Fish.1 Fish.2 MORPHO DIET
1 1 2 0.03768 0.1559250
2 1 3 0.05609 0.7897060
3 1 4 0.03934 0.4638010
4 1 5 0.03363 0.1200480
5 1 6 0.05629 0.4390760
6 1 8 0.08366 0.1866750
7 1 9 0.04892 0.0988235
8 1 10 0.04427 0.2637140
MORPHO and DIET refer to the morphological and diet distances between fish 1
and fish 2. My original data set has over 2400 pairs of fish. My goal is to
resample this dataste by selecting only 435.
I would like to do this 999 times and get a distribution of the correlation
coefficients MORPHO~DIET.
I went on and wrote this code:
head(tjornres)
essayres = tjornres # copy of the data
R = 999 # the number of replicates
cor.values = numeric(R) # store the data
for (i in 1:R) { # loop
+ group1 = sample(essayres, size=435, replace=F)
+ group2 = sample(essayres, size=435, replace=F)
+ cor.values[i] = cor.test(group1,group2)$cor
+ }
I have a syntax error in this code.
Also if I run one resampling, sample(essayres, size=435, replace=F), I get
this error message: Error in `[.data.frame`(x, .Internal(sample(length(x),
size, replace, : cannot take a sample larger than the population when
'replace = FALSE'.
Does anyone know why this code is not working? Are there any other ways to
resample (without replacement) ?
Thank you for your help,
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