To find the mean, we use the formula:

\(\bar{x} = 80 - \frac{\Sigma (x - 80)}{30}\)

\(\bar{x} = 80 - \frac{-147}{30} = 80 + 4.9 = 75.1\)

To find the standard deviation, we use the formula:

\(\text{sd} = \sqrt{\frac{\Sigma (x - 80)^2}{30} - \left(\frac{\Sigma (x - 80)}{30}\right)^2}\)

\(\text{sd} = \sqrt{\frac{952}{30} - \left(\frac{-147}{30}\right)^2}\)

\(\text{sd} = \sqrt{31.7333 - 4.9^2} = \sqrt{7.72} \approx 2.78\)