Suppose that an online advertiser wants to add some new products to its portfolio. They want to promote products that are likely to generate many clicks, and they know the brand, dollar amount, and average user review data for a huge list of products. But they have click data for only the 100 products that they have sold in the past. (a) What is the target variable 3;? If {yg} is part of the training data, what does 2' represent? What is the range of z"? (b) Suppose that they rst consider only the dollar amount, the average Google review rating (between 1 and 5), and the average Amazon review rating (between 1 and 5), assuming that all three are known for each product. Horn this data, describe how they could construct a linear model to predict the target. (c) Now suppose that they want to also incorporate the brand, which is one of A, B, or C. Describe how the linear model would change