Answer
Range = $98$
Sample variance = $s^{2}=1307.84$
Sample standard deviation = $s = 36.16$
Work Step by Step
Recall the shortcut formula for calculating the variance ($s^{2}$)$:$
$$s^{2}=\frac{\sum x_{i}^{2}-\frac{(\sum x_{i})^{2}}{n}}{n-1}$$
Create a table in which we compute $\displaystyle \sum x_{i}$ and $\displaystyle \sum x_{i}^{2}$:
$$ \begin{array}{rrr}
& x & x^{2}\\
\hline & 100 & 10000\\
& 4 & 16\\
& 7 & 49\\
& 30 & 900\\
& 80 & 6400\\
& 30 & 900\\
& 42 & 1764\\
& 2 & 4\\
\hline\rm Sum & 295 & 20033
\end{array}$$
Plug in the given values (there are $n=8$ data items):
$$\begin{align*}
s^{2}&= \displaystyle \frac{20033-\frac{(295)^{2}}{8}}{8-1} & & \\
& = 1307.84 \\\\
s&= \sqrt{1307.84} =36.16 \end{align*}$$
The range is the difference between the largest and smallest data item:
$100-2=98$
