| variable | Y | X2 | X3 | X4 |
| test value | −2.424344 | −1.829665 | −1.739393 | −2.091785 |
| The Critical Value of 10% First Order Difference | −1.604392 | −1.604392 | −1.604392 | −1.604392 |
| stationary or not | yes | yes | yes | yes |