Mark has formed an impression of juan by watching how he acts toward others during basketball practice and at school. mark has formed a(n) attribution in thinking of juan as being a team player and nice to others, regardless of the situation.
observational
situational
dispositional
error in

Mark has formed a dispositional attribution

Explanation:

A dispositional attribution consists in assigning the outcome of an event to internal personality factors.

In this example, Mark has observed that Juan is a good team leader in basketball practice. Instead of thinking that Juan is a good leader because the game requires him to act in such a way (this would be an example of a situational attribution), he considers that Juan is himself a good leader, because he has the personality characteristics of one, regarless of the situation in which he might be involved.