The expectations that girls play with barbie dolls and boys play with g. i. joe dolls are examples of:

It is a case of gender roles. A gender role is an arrangement of societal standards managing the sorts of practices which are for the most part thought to be satisfactory, fitting, or attractive for individuals in view of their real or saw sex or sexuality. 

Gender roles parts are social and individual. They decide how guys and females should think, talk, dress, and connect inside the setting of society. Learning assumes a part of this procedure of forming sexual orientation parts. These sexual orientation patterns are profoundly implanted subjective systems with respect to what characterizes manly and ladylike.

The median is 4 because 2 x’s out 9, 3 x’s out 7, 3 x’s out 5, and 4 is the only remaining number.