Answer:
Stereotype
Explanation:
A stereotype is a widely held but oversimplified notion held to a group of people or a thing. For example there are stereotypes such as: 'All Asians are good at math', 'All French people eat baguettes', 'All Americans wear cowboy hats and are overweight'.
Obviously not all Asians are good at math, not all French people eat baguettes, and not all Americans wear cowboy hats and are overweight.