a) Create a spreadsheet to find the estimates of 1,...,20 by maximizing the loglikelihood function (1,...,20). Use GRG nonlinear and force the decision variables to be Prof. Anton Braverman between two large numbers say -20 and 20. You do not need to submit a mathematical formulation for this problem. b) Verify that products that have been chosen more frequently in the data tend to have a higher vj value. Usually, vj is referred as the attraction value of the product j