The following memorandum is from the business manager of Happy Pancake House restaurants.

"Butter has now been replaced by margarine in Happy Pancake House restaurants throughout the southwestern United States. Only about 2 percent of customers have complained, indicating that an average of 98 people out of 100 are happy with the change. Furthermore, many servers have reported that a number of customers who ask for butter do not complain when they are given margarine instead. Clearly, either these customers cannot distinguish butter from margarine or they use the term "butter" to refer to either butter or margarine. Thus, to avoid the expense of purchasing butter and to increase profitability, the Happy Pancake House should extend this cost-saving change to its restaurants in the southeast and northeast as well."

Write a response in which you discuss what specific evidence is needed to evaluate the argument and explain how the evidence would weaken or strengthen the argument.