10/3 Roseanne DQ

According to the reading, Bettie explained that there was a certain "type" or "class" portrayed for either working-class or middle-class families. This is that middle-class folk are usually portrayed as almost up-scale and always thin/slender. Working-class on the other hand are usually portrayed as rude, ill-mannered, and/or fat (or bigger). So, does belonging in a certain class, either working or middle-class, determine your behavior? Are you more likely to be "classy" if you are middle-class than if you are working-class? Furthermore, why does television choose to portray people as such for each class?