Question about 1930 census from Brooklyn, NY

[carmine1917]

I have seen the census for my grandparents in 1930. Salvatore Sauli, Josephine Sauli. My father was born in 1936. This is my question, my two uncles John and Salvatore are listed but so is a daughter named Anna, age 5. Umm, who is Anna? Nobody knows. My uncles are long gone and my father has no idea!!!

On my father's birth certificate from Brooklyn, it is very blurry. In the section where it says how many children, it says 3. I also have medical records from my grandmother saying she only had 3 kids.