In her preschool classroom, kylie prefers to play with the other girls, dressing up like princesses and playing with dolls, a behavior she has seen her sister praised for at home. this example does not illustrate:

This example does not illustrate ingroup bias.
Ingroup bias refers to when you are preferring one member of your group over the rest of them, which is not the case here. Here, Kylie likes playing with girls, dressing up like a princess, etc. because it is something she learned from her sister. This behavior exemplifies gender segregation (she is playing with girls only), gender-typed behavior (she is behaving the way a girl is traditionally supposed to), and observational learning (she learned the behavior by observing her sister).