## 4 Results and Discussion
### Level 1: Descriptive Statistics
Figure 4: CO\({}_{2}\) rating of each brand. Figure 5: Smog rating of each brand. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Cylinders** & **Total Fuel Consumption (L/100 km)** & **CO\({}_{2}\) Emissions (g/km)** \\ \hline
3 & 7.78 & 181.78 \\
4 & 8.85 & 207.12 \\
5 & 10.37 & 242.43 \\
6 & 11.49 & 265.59 \\
8 & 14.00 & 318.05 \\
10 & 15.09 & 353.19 \\
12 & 16.60 & 388.24 \\
16 & 22.98 & 538.83 \\ \hline \hline \end{tabular}
\end{table} 
Table 6: CO\({}_{2}\) emissions (g/km) and total fuel consumption (L/100 km) of each cylinder. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Vehicle Class** & **Total Fuel Consumption (L/100 km)** & **CO\({}_{2}\) Emissions (g/km)** \\ \hline Station wagon: Small & 8.25 & 193.85 \\ Compact & 9.22 & 215.69 \\ Mid-size & 9.55 & 223.49 \\ SUV: Small & 10.01 & 233.65 \\ Minicompact & 10.35 & 242.16 \\ Subcompact & 10.64 & 248.95 \\ Special purpose vehicle & 10.77 & 256.90 \\ Station wagon: Mid-size & 10.86 & 254.41 \\ Full-size & 11.16 & 256.36 \\ Minivan & 11.30 & 257.98 \\ Pickup truck: Small & 11.66 & 281.61 \\ Two-seater & 12.45 & 291.33 \\ SUV: Standard & 13.25 & 303.00 \\ Pickup truck: Standard & 13.48 & 300.05 \\ Van: Passenger & 16.98 & 362.63 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: CO\({}_{2}\) emissions (g/km) and total fuel consumption (L/100 km) of each vehicle class. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Model** & **Total Fuel Consumption (L/100 km)** & **CO\({}_{2}\) Emissions (g/km)** \\ \hline IONIQ BLUE & 4.08 & 95.60 \\ IONIQ & 4.28 & 101.40 \\ PRIUS & 4.48 & 105.40 \\  &... & \\ AVENTADOR COUPE SVJ & 22.40 & 520.00 \\ DIVO & 23.00 & 537.00 \\ CHIRON PUR SPORT & 26.10 & 608.00 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: CO\({}_{2}\) emissions (g/km) and total fuel consumption (L/100 km) of each model. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Vehicle Class** & **Total Fuel Consumption (L/100 km)** & **CO\({}_{2}\) Emissions (g/km)** \\ \hline Station wagon: Small & 8.25 & 193.85 \\ Compact & 9.22 & 215.69 \\ Mid-size & 9.55 & 223.49 \\ SUV: Small & 10.01 & 233.65 \\ Minicompact & 10.35 & 242.16 \\ Subcompact & 10.64 & 248.95 \\ Special purpose vehicle & 10.77 & 256.90 \\ Station wagon: Mid-size & 10.86 & 254.41 \\ Full-size & 11.16 & 256.36 \\ Minivan & 11.30 & 257.98 \\ Pickup truck: Small & 11.66 & 281.61 \\ Two-seater & 12.45 & 291.33 \\ SUV: Standard & 13.25 & 303.00 \\ Pickup truck: Standard & 13.48 & 300.05 \\ Van: Passenger & 16.98 & 362.63 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: CO\({}_{2}\) emissions (g/km) and total fuel consumption (L/100 km) of each vehicle class. Secondly, to answer RQ1.2 (How have patterns of consumption and emission of each vehicle type changed throughout the selected period? ), descriptive statistics have been conducted for total CO\({}_{2}\) emissions and fuel consumption through the period of 2017 to 2021 in Table 9 in general. It can be seen from Table 9 that the total fuel consumption gradually increases from 2017 to 2020, before a significant drop in 2021. However, the peak in 2020 does not exist in the CO\({}_{2}\) emissions, and the value steadily rises over the entire period. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Transmission** & **Total Fuel Consumption (L/100 km)** & **CO\({}_{2}\) Emissions (g/km)** \\ \hline AV1 & 6.82 & 161.50 \\ AV & 7.13 & 167.14 \\ AM6 & 7.35 & 171.33 \\ AV10 & 7.75 & 181.29 \\ AV6 & 8.02 & 187.15 \\ M5 & 8.23 & 191.55 \\ AV7 & 8.29 & 194.37 \\ A4 & 9.05 & 212.50 \\ AV8 & 9.05 & 211.49 \\ M6 & 9.95 & 233.09 \\ AS6 & 10.39 & 237.62 \\ AS9 & 10.57 & 247.82 \\ A9 & 10.87 & 253.26 \\ AM9 & 11.00 & 259.75 \\ AS8 & 11.13 & 260.67 \\ AM8 & 11.18 & 261.78 \\ M7 & 11.32 & 264.73 \\ AM7 & 11.33 & 265.04 \\ AS7 & 12.08 & 282.10 \\ AS10 & 12.31 & 277.96 \\ A8 & 12.35 & 286.17 \\ A10 & 12.60 & 304.13 \\ A5 & 12.95 & 295.37 \\ AS5 & 13.11 & 305.64 \\ A6 & 13.15 & 288.23 \\ A7 & 13.26 & 310.85 \\ \hline \hline \end{tabular}
\end{table}