Miss Maudie says to Scout, “Atticus Finch is the same in his house as he is on the public streets.” What does this mean? What is the significance of the difference between Atticus and others in the town?

This means that Atticus is an authentic person. The beliefs and values which he communicates to his children at home are the same that he practices when he is outside the home. Atticus leads by an example which he practices in all aspects of his life. Very few people in town share Atticus's authenticity. Perhaps Miss. Maudie, Judge Taylor, and Calpurnia share these traits.