Class dichotomies

Not sure what to make of this. Classes start next week and the two classes I am teaching have online moodle sites. Student access to both sites has been ~10 days ± 5 minutes. To date my senior/graduate level course has 3.3% of students accessing the website; my sophomore level course has 18% of students accessing the website. That's a 6x difference!!! Are my sophomores more motivated than my seniors/graduate students?

Does it matter that the raw data is 1/30 students and 5/28 students respectively?