Quiz 2 Ungraded

R Markdown

#1 and #2 write two functions that takes in a numeric vector and determin the mean and the median from the values in the vector without using the mean() and median() functions.
# set seed to show the same results
set.seed(1998)
# generate a random sample between 1 and 50 with size 15
vect <- sample(1:50, size = 15)

mean_func <- function(x) {
  if (!is.numeric(x)) {
    stop("Argument vector must be numeric")
  }
  # takes the total sum of values in the vector and divides it with its length
  return (sum(x) / length(x))
}

median_func <- function(x) {
  # checks whether input vector is numeric
  if (!is.numeric(x)) {
    stop("Argument vector must be numeric")
  }
  # sorts the numeric vector just in case it is not sorted
  y <- sort(x) 
  n <- length(x)
  # checks whether the lenght of the vector is odd
  if (n %% 2 != 0) { 
    # if the length is odd then it returns the middle number
    return (y[(n + 1) / 2])
  } else {
    # if the length is even then it returns the mean of the two middle numbers
      return ((y[n / 2] + y[(n + 1) / 2]) / 2)
  }
}

mean_func(vect)

## [1] 25.46667

median_func(vect)

## [1] 24