lpossums {VGAM} | R Documentation |
Abundance of Leadbeater's Possums observed in the field.
data(lpossums)
A data frame with the following variables.
Values between 0 and 10 excluding 6.
Observed frequency, i.e., the number of sites.
A small data set recording the abundance of Leadbeater's Possums Gymnobelideus leadbeateri observed in the montane ash forests of the Central Highlands of Victoria, in south-eastern Australia. There are 151 3-hectare sites. The data has more 0s than usual relative to the Poisson, as well as exhibiting overdispersion too.
Welsh, A. H., Cunningham, R. B., Donnelly, C. F. and Lindenmayer, D. B. (1996). Modelling the abundances of rare species: statistical models for counts with extra zeros. Ecological Modelling, 88, 297–308.
lpossums
(samplemean <- with(lpossums, weighted.mean(number, ofreq)))
with(lpossums, var(rep(number, times = ofreq)) / samplemean)
sum(with(lpossums, ofreq))
## Not run: spikeplot(with(lpossums, rep(number, times = ofreq)),
main = "Leadbeater's possums", col = "blue", xlab = "Number")
## End(Not run)