probando el documento
sample(5:20,10,replace=FALSE)
## [1] 15 13 7 11 6 12 20 19 14 16
sample(70:80,size = 20,replace = TRUE)
## [1] 78 77 74 80 74 78 73 74 72 74 78 77 79 77 71 76 78 79 80 74