This kind of average, where some values are counted more times than others, is called a weighted average. The weights refer to how much each value is counted. In the above example, you could say that the categories of Gas Mileage and Cargo Space have weights equal to 1, Reliability has a weight of 2, and Interior Features/Comfort has a weight of 4. So, the total number of weights is eight. (1 for Gas Mileage, 1 for Cargo Space, 2 for Reliability, 4 for Interior Features/Comfort = 8 total weights.) Weighted average problems are specific cases of multivariable models. You might notice that the categories for rating the cars are acting as input variables used to calculate an overall score for "Car Quality" (weighted average), which is the output variable. (Q11) Which of the following represents the multivariable model used to calculate the score for Car Quality (weighted average) in the previous problem? The following variables represent the individual rating in each category: R = Reliability; G = Gas Mileage; I = Interior Features/Comfort; C = Cargo Space. i. Car Quality = frac(R+G+I+C,4) ii. Car Quality = frac(R+G+I+C,8) iii. Car Quality = frac(2R+G+4I+C,4) iv. Car Quality = frac(2R+G+4I+C,8)