The quickest and most useful way to get some basic information about a data set is to display it graphically in some way. A ternary diagram is an equilateral triangle, on each side of which is a proportional or percent scale corresponding to one of the categories. A frequency distribution is the number of times a variable takes each of its possible values. The classic example is for the sum of two dice.
Every variable has a frequency distribution.
The time you have to wait to get on an elevator or the subway, the shoe sizes of students in the class, raindrop sizes, and even the number of times Curly gets smacked by Moe in a Three Stooges film all have frequency distributions. A relative frequency distribution is formed from a frequency distribution by taking the frequency of each observed value of the variable and dividing by the total number of observations. It is especially useful when there are a large number of observations which may make the vertical scale awkward. A cumulative frequency distribution is formed by starting with the lowest value of the observed variable and its associated frequency. For each successive value of the variable, add its frequency to the total of the frequencies of all the previous values.