Pictographs and bar graphs are pictorial representations of the numerical data.

In a bar graph, each bar (rectangle) represents only one value of the numerical data.

To represent the population of different towns using bar graph, it is convenient to take one unit length to represent one person.

An observation occurring five times in a data is recorded as

, using tally marks.

In a pictograph, if a symbol represents 50 books in a library shelf, then the symbol  represents 25 books.