From what I understand (mom, correct me if I get this wrong), Betty always gave her birthday as the 7th. She said she was told that she was born late at night, but certainly before midnight. However, the hospital recorded her birth later than it actually occurred. And the newspaper announcement would come directly from the hospital records. One the other hand, the bible record follows the family tradition of the 7th. And the death certificate quotes the date Betty always used.
In this situation, we follow the family tradition of November 7th over the original birth certificate. Usually birth certificates are considered to be one of the best and most accurate documents available. However, this situation shows that any document, even the most "primary" ones available, can be suspect. Heck, my birth certificate spells my middle name wrong.