Using the Grouped Data Set Below,find the Sample Mean,variance,and Sample

Short Answer

Using the grouped data set below,find the sample mean,variance,and sample standard deviation: $$\begin{array} { | c | c | } \hline \text { Part Price } & \text { Number Purchased } \\\hline \$ 0.50 & 100 \\0.80 & 200 \\0.95 & 50 \\1.25 & 20 \\0.39 & 500 \\\hline\end{array}$$ $\bar { x }$ = ____________________.
s² = ____________________.
s = ____________________.