I've got a 11 week old great dane I've had her for 8 days I'm I little worried she has diarrhea for all of the 8 days.I changed her food the day I got her because the woman who brought my pup to me said she would bring some of her food but she didn't so I gave her some bakers for to dsys then changed her food back to beta what she was originally on.could that be the reason? She's eating and drinking normally and playing too (when she's not asleep)x

Sudden diet changes can cause diarrhea, but 8 days seems a long time for a puppy to continue. Touch base with the lady that you got her from and ask about her vaccine and deworming history. A fecal exam may be in order to check for intestinal parasites. Your vet can do this simply and quickly with a stool sample.
The benefit to having this done is to pinpoint what parasites, if any, you are dealing with. It's a good starting point.

Basically... you got a new dog, you should be taking it to the vet. Now with this problem, the vet is even more important.

When you change the dogs food the dog gets the runs. You may need to put her back on the previous dog food or gradually mix the new food a little at a time with the previous dog food to wean her on to the new food that might help. As far as the diarrhea she might be dehydrated and she will need to get some fluids in her. I would take her to the vet and have her checked out.

Dogs often will get soft stool if you just switch to a new diet without transitioning - but 8 days is far too long.
I would take her to the vet. Having diarrhea for that long may be wreaking havoc on her electrolytes. I would get her in to make sure she is okay, and see if they can find an underlying cause.

Thank everyone id did take her to the vets she had worms x