## Elementary Statistics (12th Edition)

The differences: 4, 14, -3, 1, -4, 7, 3, 4. $\overline{d}$ is the averages of the differences, hence: $\overline{d}=\frac{4+14-3+1-4+7+3+4}{8}=3.25.$ $s_d$ is the standard deviation of the differences, hence$s_d=\sqrt{\frac{\sum (x-\mu)^2}{n-1}}=\sqrt{\frac{(4-3.25)^2+...+(4-3.25)^2}{7}}=5.7.$