• the mean – arithmetic mean or average = sum(x1..xn) / n
    • appropriate for interval and ratio data
    • in physical meaning represents point of balance
  • the median – middle value of a data set when values are in ASC or DESC order
    • mathematically defined as (n+1)/2th value
    • with even number of values median is average of two middle values
  • the mode – most frequently occuring value in data set