A scatter plot is a mathematical diagram showing the relationship between two sets of data. Individual points are positioned according to the variables assigned to the vertical and horizontal axis.
For example, an ice cream shop may use a scatter plot to exemplify the effect weather has on sales, with temperature assigned to the horizontal axis, dollar amount sales along the vertical axis and dots placed accordingly. In this instance, a gradual upward slope would indicate that higher temperatures typically result in increased sales. A "trend line" may be placed through the data - with an equal number of plots data above and below it - to simplify the relationship.