Table 2 Mean test (z test) results of the five city groups.

The Z critical one-tailed value is 1.645, while the Z critical two-tailed value is 1.960.

IndexCity groupszP(Z ≤ z) one-tailedP(Z ≤ z) two-tailed
CO2 emission intensityService and high-tech cities−0.2210.4130.825
Service and light manufacturing cites−0.9510.1710.341
Service and heavy manufacturing cities−2.0330.021*0.042*
Service and energy production cities−3.1370.001*0.002*
High-tech and light manufacturing cities−1.0130.1560.311
High-tech and heavy manufacturing cities−2.310.010*0.021*
High-tech and energy production cities−3.4950.000*0.000*
Light and heavy manufacturing cities−1.6310.051**0.103
Light manufacturing and energy production cities−2.9820.001*0.003*
Heavy manufacturing and energy production cities−1.4810.069**0.139
Service sectors’ share in GDPService and high-tech cities1.4350.076**0.151
Service and light manufacturing cites2.0630.020*0.039*
Service and heavy manufacturing cities2.1770.015*0.029*
Service and energy production cities2.1070.018*0.035*
High-tech and light manufacturing cities1.0490.1470.294
High-tech and heavy manufacturing cities1.2580.1040.208
High-tech and energy production cities1.1650.1220.244
Light and heavy manufacturing cities0.2990.3820.765
Light manufacturing and energy production cities0.4250.3350.671
Heavy manufacturing and energy production cities0.2050.4190.838
Energy production sectors’ share in industrial outputService and high-tech cities0.5850.2790.558
Service and light manufacturing cites0.3040.3810.761
Service and heavy manufacturing cities0.2870.3870.774
Service and energy production cities−3.5290.000*0.000*
High-tech and light manufacturing cities−0.5050.3070.614
High-tech and heavy manufacturing cities−0.4990.3090.618
High-tech and energy production cities−4.8460.000*0.000*
Light and heavy manufacturing cities−0.0210.4920.983
Light manufacturing and energy production cities−4.9210.000*0.000*
Heavy manufacturing and energy production cities−4.8160.000*0.000*
Heavy manufacturing sectors’ share in industrial outputService and high-tech cities0.1390.4450.889
Service and light manufacturing cites0.3970.3460.691
Service and heavy manufacturing cities−1.5930.056**0.111
Service and energy production cities1.4100.079**0.158
High-tech and light manufacturing cities0.1600.4370.873
High-tech and heavy manufacturing cities−1.8770.030*0.061**
High-tech and energy production cities1.6310.051**0.103
Light and heavy manufacturing cities−4.6780.000*0.000*
Light manufacturing and energy production cities2.0340.021*0.042*
Heavy manufacturing and energy production cities5.5160.000*0.000*
Light manufacturing sectors’ share in industrial outputService and high-tech cities−0.2830.3880.777
Service and light manufacturing cites−2.0680.019*0.039*
Service and heavy manufacturing cities0.3120.3780.755
Service and energy production cities0.1960.4220.845
High-tech and light manufacturing cities−2.9920.001*0.003*
High-tech and heavy manufacturing cities1.0370.1500.300
High-tech and energy production cities0.7000.2420.484
Light and heavy manufacturing cities4.8250.000*0.000*
Light manufacturing and energy production cities3.4730.000*0.001*
Heavy manufacturing and energy production cities−0.1500.4400.881
High-tech industry’s share in industrial outputService and high-tech cities1.4630.072**0.144
Service and light manufacturing cites1.6810.046*0.090**
Service and heavy manufacturing cities1.8010.036*0.072**
Service and energy production cities2.4810.007*0.013*
High-tech and light manufacturing cities2.4810.007*0.013*
High-tech and heavy manufacturing cities2.8300.002*0.005*
High-tech and energy production cities0.5050.3070.613
Light and heavy manufacturing cities0.7840.2160.433
Light manufacturing and energy production cities0.3410.3660.733
Heavy manufacturing and energy production cities1.4630.072**0.144

*Significant at the 0.05 level.

**Significant at the 0.10 level.