Measures of center and variability. Game on.

Mean $= \dfrac{6+6+9+12+12}{5} = 9$.

Order the data and take the middle value(s): median $= 7$.

The mode is the value that appears most often. Only $4$ appears twice, so the mode is $4$.

Range $= \max - \min = 9 - 2 = 7$.

Mean $= \dfrac{3+8+10}{3} = 7$.

Order the data and take the middle value(s): median $= 5$.

Range $= \max - \min = 15 - 3 = 12$.

Mean $= \dfrac{1+4+4+7+9}{5} = 5$.