Every business collects data, and it's the job of the data analyst to analyze, interpret, and communicate that information in a way that will help drive company decisions. Employers will be looking for candidates with strong technical skills as well as a knack for conveying data in an easy to understand way. Expect a fair number of technical questions, which may include an analytical case study and a math brainteaser.
Misleading, when you invite a candidate for testing skill, you should say so.
I am currently a DOE employee at the Central office. So far I have had good experience, except with the department of Adult and Continuing Education Programs.