This is Linear Regression Analysis (Montgomery, Peck, vining)

I need someone to explaine this to me. This is example in the book Ch. 5. We also use JMP program.

\f3.0 2.0 DO output, 7 10 0.0 2 A 10 Wind velocity, x Figure 5.5 Plot of DC output y versus wind velocity & for the windmill data. TABLE 55 Observed Values y and Regressor Variable for Example 5.2 Observation Wind Velocity. DC Output, Number. i x (mph) 5.00 1.582 6.00 1.872 3.40 2. 70 0.500 10.00 2.236 9. 7 2.386 9.55 2.294 3.05 0.5.58 8. 15 2.166 6.20 1.866 2.90 0.6.53 6.35 1.930 4.60 1.562 5.80 1.737 15 7.40 2.0838 16 3.60 1.137 17 7.85 2. 179 8.80 2.112 19 7.00 1.8DO 20 5.45 1.501 21 9.10 2.303 22 10.20 2.310 23 4.10 1.194 24 3.95 1.144 25 2.45 0. 123