probando el documento
sample(5:20,10,replace=FALSE)
## [1] 14 6 15 7 19 17 18 16 20 13
sample(70:80,size = 20,replace=TRUE)
## [1] 79 77 76 78 70 70 71 78 72 72 77 71 77 79 78 72 72 78 77 75