A firm recently spent $100 on Google Adwords and generated 100 extra visits to the firm's web site, 5 of which resulted in a purchase. To pay for the change, they dropped the banner advertising on ESPN.com, saving $1000, but which also reduced the number of visits to their web site by 500, and 20 fewer sales. Sales from visitors from ESPN.com were, on average, 25% higher than sales from visitors from Google Adwords. Evaluate the decision to shift advertising money from ESPN.com to Google Adwords.