The sales by Walker's Milk and Dairy products, in millions of dollars, for the seven-year period from 2014 to 2020 are reported in the following table. a. Determine the least squares trend equation. (Round the final answers in millions of dollars to 2 decimal places.) y= b. Estimate sales for 2015. (Round the intermediate calculations and the final answer in millions of dollars to 2 decimal places.) Estimate sales for 2021 (s million)..