protocol for picking up the check

I am hosting a graduation dinner for my Granddaughter in a nice restaurant. The invitations say "hosted by" with my name.Am I responsible for picking up the entire party's bill in this instance?

Without seeing the invitation, I would have go say that you are with some caveats: Did you invite every guest that is attending? Is it an adult party? (by this I mean mostly adult family members) Are you financially able to bear the expense? Is it a small group? If you invited most of the guests and they are attending at your behest and you are financially able to take care of the bill without it becoming a huge burden and it's an intimate group (25 or so) of close family and dear friends then yes, you are responsible for the bill. HOWEVER, if your granddaughter invited a lot of her friends and the party has ballooned out of control, far past what you can comfortably afford, then your granddaughter will need to do something along the lines of sharing the expense with her parents.
Limo Princess