A marketing researcher conducted a multiple regression analysis to explain how much customers spend on a company's products (Amount Spent) as a function of four customer characteristics/variables: annual salary (Salary), number of children (Children), age (Age), and location (Location; rural or urban). Use the two partial ANOVA tables from regression analysis below to determine how much additional variation (as a percentage) in Amount Spent can be explained by Salary and Children, together, over-and-above Age and Location: Model1: Amount spent=f(age, location) SSE=37,200 MSR=11,600 MODEL 2: Amount spent= f(age, location, salary, children) (SSE: 13800) (MSR=11,650)