Chart is a graphical representation of statistical data. Different types of data require different types of charts in order to provide a meaningful representation. Some common charts are line chart, bar chart, histogram and pie chart.

Histogram is used to display distributions of interval or ratio data. It is formed by strips with width representing intervals and length representing frequencies. Despite the fact that both histogram and bar chart use strips to represent data, they have totally different meanings and usages. Different lengths of strips of bar chart represent frequencies while the width is fixed. On the other hand, strips of histogram have the property of continuity and the width represent the intervals.