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. 2021 Jul 29;7(7):e07688. doi: 10.1016/j.heliyon.2021.e07688

Table 4.

ARDL model results.

Selected Model
ARDL (3, 0, 1, 1, 1, 0, 0)
ARDL (1, 0, 0, 0, 0, 1, 1)
ARDL (1, 0, 0, 0, 0, 1, 1)
Dependent Variable ln CO2 ln CH4 ln N2O
Long run coefficients
Scale effect
 ln RGDP

1.248∗

0.4224∗

0.543∗
Composition effect
 ln Ind-ratio
 (ln Ind-ratio)2

3.985∗
0.985∗

-0.533∗∗
-0.118

-0.488∗∗
-0.061
Technique effect6
 ln GNDI
 (ln GNDI)2

-0.167
-0.039∗

1.201∗
-0.077∗

0.803∗
-0.057∗
ln FEC 1.399∗ 0.259∗∗ 0.236∗∗

Short run coefficients
Scale effect
 Δ(ln RGDP)

0.965∗

0.198∗

0.372∗
Composition effect
 Δ (ln Ind-ratio)
 Δ (ln Ind-ratio)2

1.125
-0.183

-0.249∗∗
-0.055∗∗∗

-0.308∗∗∗
-0.042
Technique effect
 Δ (ln GNDI)
 Δ (ln GNDI)2

-1.085∗
-0.031∗

0.562∗
-0.007∗∗∗

0.551∗
-0.010∗∗
Δ (ln FEC) 0.727∗ 0.036 0.056
Error correction term -0.774∗ -0.468∗ -0.686∗

Model Diagnostic tests
R2
[adj-R2]
0.992
[0.989]
0.991
[0.989]
0.985
[0.982]
Breusch-Godfrey Serial Correlation LM Test [P-Value] 0.130
[0.878]
2.335
[0.114]
0.267
[0.609]
Heteroscedasticity Test: ARCH [P-Value] 1.036
[0.315]
0.274
[0.603]
0.089
[0.766]
Ramsey RESET Test
[P-Value]
0.056
[0.814]
0.294
[0.592]
1.416
[0.243]
Normality: JB test
[p-value]
0.056
[0.972]
3.058
[0.217]
0.111
[0.946]

Note: ∗, ∗∗ and ∗∗∗ denote significance at 1 %, 5 % and 10 % levels, respectively. The optimal lag structure for each model is automatically selected based on Akaike Information Criteria (AIC).