Variable

Coefficient

Std. Error

t-Statistic

Prob.

C

42.7408

68.9797

0.6196

0.5390

$X_5^2$

28.6836

6.8367

4.1955

0.0001

$X_5\ast X_6$

−6.8208

3.0145

−2.2626

0.0292

$X_5\ast X_2$

−1.1750

1.1410

−1.0298

0.3093

$X_5$

8.3427

29.2861

0.2849

0.7772

$X_6^2$

0.0982

0.4634

0.2118

0.8333

$X_6\ast X_2$

0.1565

0.3930

0.3982

0.6926

$X_6$

2.7742

7.6312

0.3635

0.7181

$X_2^2$

0.1953

0.0855

2.2842

0.0277

$X_2$

−6.7063

4.8997

−1.3687

0.1787

R-squared

0.6947

Mean dependent var

7.1936

Adjusted R-squared

0.6261

S.D. dependent var

16.5281

S.E. of regression

10.1069

Akaike info criterion

7.6412

Sum squared resid

4085.9430

Schwarz criterion

8.0236

Log likelihood

−181.0290

Hannan-Quinn criter

7.7868

F-statistic

10.1158

Durbin-Watson stat

1.6708

Prob (F-statistic)

0.0000