I think that it depends on the task that they are doin.
If a group of people are opening up service with praise and worship then they are probably a Praise Team.
If a group of people are singin and A or B selection, they are problably a choir. But then I would also say that it depends on the size of the church(meaning amount of members). If the church has 5000 members you cant it to have a small praise team. or a small choir.
Now if yo church only has 20 members then you know that the big sista thats at the front of the church is the praise team. LOL (I miss thoughs days)