(g) These effects are the interaction effects between CFO and each one of the other explanatory variables. (h) See the details in Excel. (i) According to the p-values of all the 5 tests in (h), only the test for "wv.s ," is significant at o = 0.05, which means 2, is the only more reasonable choice than the reduced model w. (j) See the plot in Excel. From the plot, we we can see that the 4 regression lines are not parallel to each other, which means YEAR and CFO have interaction effects. And as the years leading to the Second World War, the negative relationship between PBE and CFO decreases (with the absolute values of slope change smaller as YEAR increase)