Some of the services offered by Boyle's gyms, especially those provided by individual trainers, may vary in quality, which is best described as _______.
Heterogeneity refers to the quality of various thing varying in their character and fundamental way of existence. It simply refers to diversity. The Individual Trainers are different people and as such they have different mindsets and ways of doing certain things. As such, they cannot be expected to provide the exact same service. The services they provide will vary but probably not by much.
