Final answer:
The unspoken expectation of being 10-15 minutes late to a group meeting without notice exemplifies a 'social norm', which represents the expected behaviors within a group or society.
Step-by-step explanation:
The unspoken expectation in Deondra's social group on campus, where it is acceptable to be 10-15 minutes late without needing to call and check in, is an example of a social norm. Social norms are groups' expectations of what is appropriate and acceptable behavior for its members, and they can include how they are supposed to behave and think. These are the unwritten rules that people in a society or group follow without often realizing, and they help maintain order and predictability within the group.