A dot plot, also known as a line plot, is a way to represent numerical or categorical data in which each data point is represented with a dot above a horizontal line with numbers or categories. Dots representing the same measurement are stacked above each other. Consider the following data set.

• There are two $1\text{s}$ in this data set, so two dots are stacked above the number $1$ on the number line of the corresponding dot plot.
• There is one $3$ in this data set, so a single dot is drawn above number $3.$
• There are five $4\text{s}$ in this data set, so five dots are stacked above number $4$ on the number line.

Dot plots are normally used for discrete data. For data sets containing more than $20$ data points, dot plots are often inconvenient and other representations are preferred.