In terms of social class, the average American may be described as either being middle or working class. As social classes lack distinct boundaries the average American may have a status in the area where the lower middle and upper working class overlap.
Today, one can no longer refer to the nuclear family as the average American household, neither can one identify the current plurality of married couples without children as "the average." Recent statistics indeed indicate that there is no average American family arrangement, but that American society is home to a wide and diverse variety of family arrangements. The one thing the data does indicate is that the average Joe most likely does not reside in a nuclear 4-person family.