A line plot is a one-dimensional display in which a line is used to represent each point. The line plot directly below the histogram includes one line per variable value.
In contrast to the other univariate plots, a line plot is not smoothed. It directly shows the values of the variable. Thus, a line plot is useful for spotting groupings of values, outliers, and so forth.
Note that if a variable value occurs on more than one observation, it is reflected by only a single line in the line plot. The X-axis of the histogram provides the scale for the line plot.