Question for Ted or other Financial Whiz

Ted had recommended parking cash in the Vanguard VBISX - Mostly a short term treasury Bond Fund. And considered this almost as safe as a Money Market fund.

However when researching this Morningstar rates this Fund Risk Status as above average - Whatever that means.

Here is the link :


http://finance.yahoo.com/q?s=vbisx

Ted - or anybody can you explain this to me?

Thanks,