The marginal distributions are a useful addition to a scatterplot
When dealing with bivariate data, the univariate distributions of the separate variables are called their marginal distributions. Although they do not contain information about the relationship between the variables, a display of the marginal distributions can be usefully added to a scatterplot to enhance it.
House prices in Palmerston North
The following scatterplot shows information obtained from a sample of 141 real estate sales records from two suburbs of Palmerston North for houses built in the last thirty years. Box plots have been added to the margins of the scatterplot.
The box plots shows the skewness of both individual measurements.
(We will discuss other features of this scatterplot in the next section.)
The scatterplot below shows the same data with histograms displaying the two marginal distributions.