Im very new to R and am getting stuck on what I thought would be the easiest part of what im trying to do. Im generating numbers at 5 time points and looping the simulation, but am stuggling to return the means of the generated numbers. The data frame is;

time, n

1 , *n1*

2 , *n2*

3 , *n3*

4 , *n4*

5 , *n5*

Nsp<-c()

for(i in 1:10) {

tree<-sim.bd(b=0.308, d=0.2926, n0=5448, times=0:4)

Nsp[i]<- rowMeans(tree[c("n")])

}

However this doesnt work as I am only selecting one value for in each row. Ive tried 'Nsp[i]<- rowMeans(subset(tree, select = c(n)))' however this gives the error 'number of items to replace is not a multiple of replacement length'. I though extracting the averages of the values created was the simple part.