What can we gather about the social classes of Nick Carraway and the Buchanans? What do each of them believe about how the world works?

Nick's history seems to be upper middle class and quite "normal" as opposed to the vapid elite of East Egg. Nick is a pretty credible character. He doesn't have any eccentricities and seems grounded. He was educated at the Ivy School Yale and fought in WW1. Nick isn't a character who needs anything. He seems to have enough money to settle down in West Egg. He has come to New York for work and to learn the bond business; he doesn't seem to be in a hurry to get started. Nick's Midwestern sensibilities are juxtaposed with the likes of Tom Buchanan. Tom comes from old money and knows nothing but the extravagance and entitlement of the ultra-rich.

Thanks