Solve $\sigma =\sqrt{\frac{\sum (x_i-\mu {)}^2}{N}}$

Step-by-step solution

1. Step 1 · Population mean
   $$\mu =\frac{40}{8}=5$$

   Deviations are measured from the mean.

2. Step 2 · Sum of squared deviations
   $$\sum (x_i-\mu {)}^2=32$$

   9 + 1 + 1 + 1 + 0 + 0 + 4 + 16 = 32.

3. Step 3 · Divide by N and take the root
   $$\sigma =\sqrt{\frac{32}{8}}=2$$

   Population form divides by N, not N − 1.