Aunt Alexandra comes to stay with Jem and Scout during the trial. She is and always has been disapproving of the way Atticus has raised his children. She refers to Scout always as "Jean Louise" and thinks she is a tomboy, ruffian and unfeminine. She tells the children:
"Jem's growing up now and you are too," she said to me. "We decided that it would be best for you to have some feminine influence. It won't be many years, Jean Louise, before you become interested in clothes and boys--"
She tries to get Scout to wear dresses and act more like a girl and even "encourages" her to attend her women's missionary tea.
She also thinks Scout is dumb:
It was plain that Aunty thought me dull in the extreme, because I once heard her tell Atticus that I was sluggish.
She also thinks Jem is wild and that he does not appreciate his lineage:
Your aunt has asked me to try and impress upon you and Jean Louise that you are not from run-of-the-mill people, that you are the product of several generations' gentle breeding --' Atticus paused, watching me locate an elusive redbug on my leg.
"Gentle breeding," he continued, when I had found and scratched it, "and that you should try to live up to your name--
Read the helpful information here on eNotes. Also, Aunt Alexandra arrives in chapter 13, so you should go back over that chapter and find additional examples. Good luck!