Three made-up kites fly in winds of 1, 2 and 3 m/s, and reach heights of 2, 5 and 6 m…

Step 1. Slope. $S_{xx} = 1 + 0 + 1 = 2$ and $S_{xy} = \dfrac{7}{3} + 0 + \dfrac{5}{3} = 4$. So $b = \dfrac{4}{2} = 2$ m per m/s.

Step 2. Intercept. $a = \dfrac{13}{3} - 2 \times 2 = \dfrac{1}{3} = 0.333$ m.

Step 3. Residuals. The predictions are $2.333$, $4.333$ and $6.333$ m. The residuals are $-\dfrac{1}{3}$, $\dfrac{2}{3}$ and $-\dfrac{1}{3}$ m. They add up to $0$.

Step 4. SSE. $\dfrac{1}{9} + \dfrac{4}{9} + \dfrac{1}{9} = \dfrac{6}{9} = 0.667$.