The steps for the Chow test follow:

Step 1: Run regression on all data                      Obtain RSS₁ = 19953.78; df = 20

Step 2: Run regression on 1970-1980's data      Obtain RSS₂ = 1010.842; df = 9
            Run regression on 1980-1991's data      Obtain RSS₃ = 5103.470; df = 9

Step 3: Add RSS₂ and RSS₃                             Obtain RSS₄ = 6114.312;  df = 18

Step 4: Subtract RSS₄ from RSS₁                     Obtain RSS₅ = 13839.468

Step 5: Compute F_8,8,4

                               F_8,8,4  = (RSS₅ / k) / [ RSS₄ / (n₁ + n₂ - 2k)]
                                         = (13839.468 / 2) / (6114.312 / 18)
                                         = 20.371

Step 6: Find F^C_0.05,2,18 = 3.55

Conclusion: Reject the null hypothesis that the marginal propensity to save (MPS) out of personal income was the same from 1970-1980 and 1981-1991.