Final answer:
The teacher in question is engaging in stereotyping, which is the application of generalized beliefs to all members of a group.
Step-by-step explanation:
A teacher who thinks that all Catholic families are over-involved in their kids' lives is engaging in stereotyping. Stereotyping involves applying a generalized belief or assumption to all members of a particular group, regardless of individual differences. It's a form of social categorization that can lead to oversimplified and often inaccurate perceptions of people. In an educational setting, it is particularly problematic as it can affect the teacher's expectations and interactions with students.