Why does Aunt Alexandra move into the Finch household?

When the trial is imminent, Aunt Alexandra shows up at the Finch home and announces that she’s there to stay for the benefit of Jem and Scout. She and Atticus agree that Jem and Scout may need round-the-clock supervision during the public spectacle, and she believes that the children need more exposure to the propriety and traditions of their upstanding family. Aunt Alexandra also believes that Scout needs to be taught to be a perfect Southern lady who knows how to wear a dress, serve tea, and converse with other women.