3. Refer to the Regression analysis worksheet. To understand the effectiveness of its marketing strategies, ABC Co. tracks its adver- tisement expenditures and sales in every marketing campaign. There are 3 variables contained in the dataset provided by ABC. i Influencer type Macro or Nano ii Sales ($ thousands) Sales from the marketing campaign iii Social media ($ thousands) Advertisement expenditures on social media of the marketing campaign (c) [5 marks] The marketing manager believes that Macro influencers provide a greater return to sales per advertisement dollar spent. Estimate a multiple linear regression model to test whether the empirical data supports her beliefs. Write down the estimated regression model