## Description: Functions vars1, vars2, vars3, and vars4 compute both the
##              empirical variance and the MLE of population variance
## Arguments:
##    x: A numeric vector
##
## Note: Function varML must already exist
##
## Codes:


#ahora puedo escribir varias funciones:

## Function vars1
vars1 <- function(x)
{
  stopifnot(is.numeric(x))

  val1 <- var(x)
  val2 <- 0.5*var(x)
  return(val1)
  return(val2)
}


## Function vars2
vars2 <- function(x)
{
  stopifnot(is.numeric(x))

  val1 <- var(x)
  val2 <- 0.5*var(x)
  print(val1)
  cat("ML estimator:", val2, "\n")
}


## Function vars3
vars3 <- function(x)
{
  stopifnot(is.numeric(x))

  val1 <- var(x)
  val2 <- 0.5*var(x)
  return(list("Empirical variance" = val1,
              "ML estimator of the variance" = val2))
}


## Function vars4
vars4 <- function(x)
{
  stopifnot(is.numeric(x))

  val1 <- var(x)
  val2 <- 0.5*var(x)
  vars <- c(val1, val2)
  names(vars) <- c("Var", "VarML")
  return(vars)
}