iOS5 NSManagedObjectContext Concurrency types and how are they used?

Question

Literature seems a bit sparse at the moment about the new NSManagedObjectContext concurrency types. Aside from the WWDC 2011 vids and some other info I picked up along the way,

Answer 1

midas06 wrote:

Imagine having a parent context that does all io on a background thread that is a private queue context, and then you do all your ui work against a child context of the main queue type.

I understood it to be the other way around: you put the parent context on the main thread using NSMainQueueConcurrencyType and the child context on the background thread using NSPrivateQueyeConcurrencyType. Am I wrong?