The Kaski & Untiedt Family Trees

I've been digging through old Census records again, and I'm struggling with how to correctly interpret a marking from a 1850 US Census page in Illinois. See yellow circles below. They look like a "0" or an "O". I initially thought they meant "same as above" or "ditto", but I'm not sure anymore, and Google was not helpful.  In the example above, the first row is Pa for Pennsylvania. Does that mean the second row is also Pennsylvania? Or does that mean "Illinois" which is the state where the census was taken? The census taker also wrote ditto marks, so why use "0" to mean the same thing? Row 4 is what really made me wonder; which one is it? Rows 3-8 are all the same family.      Row 3 is the father and Pennsylvania is the answer.       Then row 4 is the mother and has quotation marks, which I assume means Pennsylvania.     Row 5 is then the oldest child, and it has the unknown marker, "0". If the unknown ma...