Scout is likely inquiring because she wants to know if the rumors she's heard are true. She is seeking confirmation of or evidence against these rumors. Plus, they wonder about what he really looks like, how healthy he appears and what life looks like in that home.
Atticus' response of nothing to Scout is significant because it reflects his character and parenting style. He prevents situations from happening or getting worse by treating children like little adults and Scout easily read his signal to not go on and on nagging him (like most kids would) about what she wants. She took his answer at face value and went on about her business.
The incident that you are talking about happens in Chapter 8. Mrs. Radley has died and Atticus has gone over to visit.
Scout asks Atticus about the visit -- specifically, she asks Atticus if he saw Boo Radley there. The reason she asks is because she and the others are still obsessed with Boo and with the Radleys in general.
Atticus essentially tells her nothing. All he says is that he did not see Boo. He does also tell them that Mrs. Radley has died of natural causes. But he says this before Scout asks him anything.
Well at this part Mrs. Radley has died and Atticus has gone to visit. When Scout asks, she is curious about Boo Radley and wants to know what he thought. He does not really talk about Boo though. Scout is curious because at that age they were very curious at how Boo looked and how he was.
how old do you have to be to get your doctorate degree?