The manger of a city coffee shop is thinking about adding a small art gallery to her shop to display the work of local artists. First, she decides to gather some opinions on whether or not this is something her customers would enjoy.
To do this, the manager places surveys at the counter and on the tables of the coffee shop. Customers can fill out a survey and return it to any store employee.
Identify the sampling method being described AND describe a potential problem that could result from using this type of sample.