Dependent Variable

Copper Price

Variable X_t

Variable X_t

ADF Test

(p value)

lags

ADF Test

(p value)

lags

Copper Prodution

−2.9077

0.1452

1

−0.3247

0.9745

11

Brent Price

−2.7422

0.1956

1

−1.4526

0.7813

2

Aluminum Price

−2.9082

0.1449

0

−2.5790

0.2555

0

Copper Stocks

−2.4427

0.3131

1

−2.8681

0.1564

2

Exchange Rate

−2.6980

0.2109

1

−0.6989

0.9446

1

Industrial Prodution

−1.9933

0.5346

1

−1.0830

0.8858

4