Answer
$\bar x_{d} = 2$
$s^{2}_{d} = 2$
Work Step by Step
Difference
7 - 4 = 3
3 - 1 = 2
9 - 7 = 2
6 - 2 = 3
4 - 4 = 0
8 - 7 = 1
$\bar x_{d} = \frac{3+ 2+ ... + 1}{6} = 2
$s^{2}_{d} = \frac{(3-2)^2 + .... + (1 - 2)^{2}}{6 - 1} = 2