Figure 2
The line chart shows two side-by-side panels. The left panel has a horizontal axis with years from 1990 to 2020 in increments of 5 years and a vertical axis ranging from negative 20 to 20 in increments of 5 units, and includes a legend labeled “C U S U M” and “5 percent Significance”. The line representing “C U S U M” starts with the point (1990, negative 2), passes through (1995, 2), (2000, 1), and (2010, 4), and ends at (2020, 0). The upper 5 percent significance line starts from (1990, 7) and ends at (2020, 17) showing the positive slope, and the lower 5 percent significance line starts from (1990, negative 7) and ends at (2020, negative 17) showing the negative slope. The right panel has a horizontal axis with years from 1990 to 2020 in increments of 5 years and a vertical axis ranging from negative 0.4 to 1.4 in increments of 0.2 units, and includes a legend labeled “C U S U M of Squares” and “5 percent Significance”. The line representing “C U S U M of Squares” starts with the point (1990, 0.0), passes through (1995, 0.4), (2005, 0.7), and (2015, 0.9), and ends at (2020, 1.0). The upper 5 percent significance line starts from (1990, 0.4) and ends at (2020, 1.2) showing the positive slope, and the lower 5 percent significance line starts from (1990, negative 0.1) and ends at (2020, 0.7) showing the positive slope. Note: All numerical data values are approximated.Plot of cumulative sum of recursive residuals and sum of squares of recursive residuals: interaction model. Source(s): Authors’ work