\( \definecolor{colordef}{RGB}{249,49,84} \definecolor{colorprop}{RGB}{18,102,241} \)
The following data shows the math marks (out of 20) obtained by a group of students: $$4,\ 12,\ 9,\ 7,\ 11,\ 15,\ 8,\ 6,\ 14$$Find the range of the marks.