Histogram

A histogram is a graphical representation in which all the data are grouped into user-specified ranges and presented in the form of bars. Mathematically, a histogram is a function that counts the number of observations that fall into each of the bins or ranges.

Example
 

Age of the students has been split into bins, with each bin representing a 10-year period starting at 20 years. The second row represents the number of students from the dataset that fall within that range.

Based on the shape of the histogram, they can be categorized as symmetric, skewed left, skewed right, unimodal, bimodal or multimodal.