(a) To find the standard deviation, we first calculate the variance using the formula:

\(\text{Var} = \frac{\Sigma (x - q)^2}{50} - \left(\frac{\Sigma (x - q)}{50}\right)^2\)

Substitute the given values:

\(\text{Var} = \frac{14235}{50} - \left(\frac{700}{50}\right)^2\)

\(\text{Var} = 284.7 - 196 = 88.7\)

The standard deviation is the square root of the variance:

\(\text{sd} = \sqrt{88.7} \approx 9.42\)

(b) Given \(\Sigma x = 2865\), we use the equation:

\(\Sigma x - 50q = 700\)

Substitute \(\Sigma x = 2865\):

\(2865 - 50q = 700\)

Solve for \(q\):

\(50q = 2865 - 700\)

\(50q = 2165\)

\(q = \frac{2165}{50} = 43.3\)