Yellow is fake gold; it's veneer and show rather than substance. We see that with the yellow cocktail music at Gatsby's party (1) and the two girls in twin yellow dresses who aren't as alluring as the golden Jordan (3.15).
I think a moderate income is income above the median for famlies in your county, but not more than 25% of the median income. The IRS usually has this info for free, but I see they are now charging $10 for this on their web site for more recent years. http://www.irs.gov/taxstats/indtaxst...=96947,00.html.
Household income is an economic measure that can be applied to one household, or aggregated across a large group such as a county, city, or the whole country. It is commonly used by the United States government and private institutions to describe a household's economic status or to track economic trends in the US.