Greater Median Income Reported in the East

Many of us are going to be graduating soon and looking for jobs to pay for the last four years of debt acquired to obtain our bachelor degrees. According to the census data released last Tuesday, the highest median incomes were recorded in the eastern states consisting of New Jersey, Maryland, Massachusetts and New Hampshire. The median income in these areas is above $56,000 compared to the national average of $43,000. The states reporting the lowest median income are West Virginia, Louisiana, Mississippi, Montana and Arkansas. One thought that comes to mind is how large of a role does the cost of living play in the east, as I have seen in areas such as California and New York; the wages are not equal to the increasing costs of living. Although, I know in these areas the cost of living may influence the median income to somewhat compensate for the costs. Would this be the reason the median income is higher or would it be the fact that people are merely compensated more for their performance?