Answer
Median: $3$
Mode: $10$
Mean: $4$
Work Step by Step
Arrange data in ascending order:
$$-9,-2,0,3,3,10,10,10,11$$
The median is middle value $3$.
The mode is $10$, that occurs most often.
The mean is:
$$\frac{-9+(-2)+0+3+3+10+10+10+11}{9}=\frac{36}{9}=4$$