2 A traffic camera measured the speeds, \(x\) kilometres per hour, of 8 cars travelling along a certain street, with the following results.
$$\begin{array} { l l l l l l l l }
62.7 & 59.6 & 64.2 & 61.5 & 68.3 & 66.9 & 62.0 & 62.3
\end{array}$$
- Find \(\Sigma ( x - 62 )\).
- Find \(\Sigma ( x - 62 ) ^ { 2 }\).
- Find the mean and variance of the speeds of the 8 cars.