I got a different package name format

I have uploaded the screen shot when I am trying to create a 2nd activity. I somehow notice that the Package name of my screen reads as com_bignerdranch_android.geoquiz instead of com.bignerdranch.android. Upon looking back, I found out that it is already this format in chapter one.
I now need to fill in the package name in the New Empty Activity wizard. I guess I should keep the old format. Can anyone help to find out why I am different?

tools:context = "xxx"
The xxx represent your class package name