If they asked me how much money I had in savings, I would guess they are referring to money I have either in a savings account, or with an investment firm or somehow saved for my retirement. And not specifically in a savings account.
According to the article, the question they asked is literally, "How much money do you have saved in your savings account?"
The results are not really too dissimilar from the Fed study sited by The Atlantic earlier this year. In my not so humble opinion the question asked as part of the Fed study is more robust but the conclusion is similar.
http://www.theatlantic.com/magazine/archive/2016/05/my-secre...