Using exponential smoothing, the forecast for time period 20 equals the forecast for time period 19 plus O a times (the actual value in time period 19). O a times (the forecast error for time period 19). O a times (the forecast error for time period 18). a times (the forecast for time period 18). Question 8 2 pts Interaction exists in a multiple regression model when: the regression model is significant. one independent variable affects the relationship between another independent variable and the dependent variable. correlations among variables are present in a regression model O a quadratic model is used