First, find the mean of the speeds:

\(\bar{x} = 50 + \frac{81.4}{22} = 53.7\)

Next, calculate the variance using the formula:

\(\text{Var} = \frac{\Sigma(x - 50)^2}{22} - (\bar{x} - 50)^2\)

\(\text{Var} = \frac{671}{22} - 3.7^2 = 16.81\)

To find \(\Sigma x^2\), use the expanded equation:

\(\Sigma x^2 = \Sigma(x - 50)^2 + 2 \times 50 \times \Sigma(x - 50) + 22 \times 50^2\)

\(\Sigma x^2 = 671 + 2 \times 50 \times 81.4 + 22 \times 2500\)

\(\Sigma x^2 = 671 + 8140 + 55000 = 63811\)