In social network analysis, groups can become too insular and fail to share what they have learned with people outside the group. this is a result of

I believe the answer is: closure

Closure cause the members in a group to have underlying assumption that other people from outside their group would behave in the exact same way as their group do. Having this point of view would make them become unprepared when their collective view is challenged by differing opinion.

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.