As shown by the dot plots, Group A has one 9-year-old painter, seven 10-year-old painters, and 24 painters between the ages of 15 and 20. Group B has seventeen painters between the ages of 10 and 20 and thirteen painters between the ages of 25 and 30. Since mean is the average of everything, Group A most likely has a lower mean age of painting students than Group B does.