dados <- data.frame(h=c(18.79, 12.34, 14.11, 15.24, 13.82, 14.54, 13.77, 13.99, 10.00, 16.80, 10.49, 20.00, 14.19, 14.09, 14.65, 12.22, 16.21, 13.90, 16.29, 15.39), parc=rep(1:4, each=5), arv=rep(1:5, 4))
{set.seed(765); sorteio <- lapply(10:1, function(x) unlist(sample(seq(dados[,1]),x)))}
sorteio
datasets <- lapply(sorteio, function(x) dados[unlist(x),]); datasets
medias <- sapply(sorteio, function(x) c(colMeans(dados[unlist(x),]), n=length(x))); medias
soma <- sapply(sorteio, function(x) c(colSums(dados[unlist(x),]), n=length(x))); soma
### </code>