> On 30 Mar 2016, at 02:53, Marine Regis <marine.re...@hotmail.fr> wrote: > > Hello, > > I would like to build a Lorenz curve and calculate a Gini coefficient in > order to find how much parasites does the top 20% most infected hosts support. > > Here is my data set: > > Number of parasites per host: > parasites = c(0,1,2,3,4,5,6,7,8,9,10) > > Number of hosts associated with each number of parasites given above: > hosts = c(18,20,28,19,16,10,3,1,0,0,0) > > To represent the Lorenz curve: > I manually calculated the cumulative percentage of parasites and hosts: > > cumul_parasites <- cumsum(parasites)/max(cumsum(parasites)) > cumul_hosts <- cumsum(hosts)/max(cumsum(hosts)) > plot(cumul_hosts, cumul_parasites, type= "l”)
Your values in hosts are frequencies. So you need to calculate cumul_hosts = cumsum(hosts)/sum(hosts) cumul_parasites = cumsum(hosts*parasites)/sum(parasites) The Lorenz curves starts at (0,0), so to draw it, you need to extend these vectors cumul_hosts = c(0,cumul_hosts) cumul_parasites = c(0,cumul_parasites) plot(cumul_hosts,cum9l_parasites,type=“l”) The Gini coefficient can be calculated as library(reldist) gini(parasites,hosts) If you want to check, you can “recreate” the original data (number of parasited for each host) with num_parasites = rep(parasites,hosts) and gini(num_parasites) will also give you the Gini coefficient you want. > >> From this Lorenz curve, how can I calculate the Gini coefficient with the >> function "gini" in R (package reldist) given that the vector "hosts" is not >> a vector of weights ? > > Thank you very much for your help. > Have a nice day > Marine > > > [[alternative HTML version deleted]] > > ______________________________________________ > R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code.
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______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.