The graphical method for studying the behavior of the seasonal time series. In such a plot, the January values of seasonal component are graphed for the upcoming years, then the
February values are graphed, and so on. For each monthly subseries the mean of values is represented by the horizontal line. The graph permits an assessment of the overall pattern of seasonal change, as portrayed by horizontal mean lines, as well as the behavior of each of the monthly subseries. Since the entire latter are on the same graph it is readily seen whether the change in any subseries is big or small compared with that in the overall pattern of seasonal component. The plot is shown in the figure drawn below