An electronics company is looking to develop a regression model to predict the number of units sold for a special running watch. Data is provided below:
Sales (units) Price ($) Advertising ($) Holiday
500 100 50 Yes
480 120 40 Yes
485 110 45 No
510 103 55 Yes
490 108 40 No
488 109 30 No
496 106 45 Yes
1. Compile an excel spreadsheet for the above data and determine the regression equation.