What is the purpose of a line of best fit in a scatter plot?

The purpose of a line of best fit in a scatter plot is to illustrate the relationship between the variables being analyzed. This line is drawn so that it best represents the trend of the data points, capturing the overall direction and pattern they exhibit. By doing so, the line helps to summarize the relationship visually, making it easier to interpret the correlation—whether it be positive, negative, or nonexistent—between the two variables.

A line of best fit does not necessarily connect all points directly; rather, it aims to minimize the distance from the points to the line, therefore fitting most of the data and reflecting the general trend of the dataset. It could also enable the prediction of future data points based on the established relationship, but the primary function is to portray the relationship between the variables clearly and concisely. Thus, it is not used to represent the average of the dataset but rather the underlying trend that the data points follow.