testfordiff.ind.pval {QFASA} | R Documentation |
Test for a difference between two independent samples of compositional data. Zeros of any type are allowed.
testfordiff.ind.pval(compdata.1, compdata.2, ns1, R = 500)
compdata.1 |
sample of compositional data. |
compdata.2 |
sample of compositional data. |
ns1 |
sample size of compdata.1. |
R |
number of bootstrap samples, default is 500. |
p-value obtained through a multivariate permutation test with test statistic based on chi-square distances.
Stewart, C., Iverson, S. and Field, C. (2014) Testing for a change in diet using fatty acid signatures. Environmental and Ecological Statistics 21, pp. 775-792.
## Prey data(preyFAs) ## Capelin FA sig capelin.sig=preyFAs[preyFAs$Species=="capelin",4:(ncol(preyFAs))] capelin.sig=capelin.sig/apply(capelin.sig,1,sum) ## Sandlance FA sig sandlance.sig=preyFAs[preyFAs$Species=="sandlance",4:(ncol(preyFAs))] sandlance.sig=sandlance.sig/apply(sandlance.sig,1,sum) # Note: uncomment examples to run. CRAN tests fail because execution time > 5 seconds # testfordiff.ind.pval(as.matrix(capelin.sig), # as.matrix(sandlance.sig), # nrow(capelin.sig))