Answer
See below.
Work Step by Step
The mean of $n$ numbers is the sum of the numbers divided by $n$. The median of $n$ is the middle number of the numbers when they are in order (and the mean of the middle $2$ numbers if $n$ is even). The mode of $n$ numbers is the number or numbers that appear(s) most frequently.
Hence here the mean: $\frac{-3+ 5+(-11)+ 6+(-3)+ 2}{6}=0.67$, the median is the mean of the middle items in the sequence $-11,-3, -3, 2,5, 6$, which is: $(-3+2)/2=-0.5$, the mode is $-3$.
The range is the difference between the largest and the smallest data value. The standard deviation of $x_1,x_2,...,x_n$ is (where $\overline{x}$ is the mean of the data values): $\sqrt{\frac{(x_1-\overline{x})^2+(x_2-\overline{x})^2+...+(x_n-\overline{x})^2}{n}}$.
Hence here the range is: $6-(-11)=17$ and the standard deviation is: $\sqrt{\frac{(-3-0.67)^2+(-5-0.67)^2+...+(2-0.67)^2}{6-1}}\approx6.3456$
