An ecommerce chart compares visitor segments. A bar chart compares revenue per visit for New users, Returning users, Members, and Guests. The data labels are New users: $18.5; Returning users: $19.1; Members: $19.8; Guests: $20.0. The vertical axis runs from $18.0 to $20.5, not from zero. Which comparison between Guests and New users is most defensible?