An overgeneralization about an entire group of people is

The right answer is the stereotype.

In social psychology, a stereotype is:

* A belief that a person maintains about the characteristics of the members of an outgroup;

* A generalization affecting a group of people and differentiating them from others. Stereotypes can be over-generalized, inaccurate and resist new information.

you can show her once, and if she doesn't do it, do what i do: i take away one of her privileges until she learns. it worked for my sister but note every child is different. or you canput her on 'time out' if she doesn't learn.