It is probably best to assign this self-assessment questionnaire as a homework assignment, encouraging students to take their time in responding (which increases response validity). In discussing the results, pose these questions to students: 

Consider your scores in each of the four areas. Now, think back on your past life experiences. Are there experiences or specific influences that significantly affected one or more of these four dimensions of your personality? 

Some personality theorists/researchers believe that once you've turned 30 or so, your personality is basically etched in stone (unchangeable). Do you agree? Could your scores change on these dimensions? If so, what factors might bring about change?