Table 5: The correlation coefficients matrix of the explanatory variables.

Variables

 X1 X2 X3 X4
X1

1

0.229

-0.824*

-0.245
X2

0.229

1

-0.139

-0.973*
X3

-0.824*

-0.139

1

0.030
X4

-0.245

-0.973*

0.030

1

Note: *Correlation is significant at 0.05.