Exercise

NC High Income Zips

Did you have a hypothesis of why certain zip codes are missing income information? It looks to me like many of them are areas that likely have low populations (e.g., parks, colleges, etc.) and the IRS only reports income data on zip codes with more than 100 filers.

Now let's focus in on a subset of zip codes with income data, namely the 25% of zip codes in NC with the highest mean incomes. Where do think these will fall within the states?

Let's take a look and find out.

Instructions 1/3

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Summarize the mean income variable to find the cut point for the top quartile of mean income.