# AI-Driven Predictive Maintenance for Workforce and Service Optimization in the Automotive Sector
## 3 Preliminaries
### Data Analysis
#### 3.3.1 Descriptive Statistics
The Visits feature is binary, representing whether a vehicle visited the service center (1) or not (0) during a given month. As shown in Table 5, the mean value for visited records is 1.00, as all visited records inherently reflect a service visit. Similarly, the standard deviation and median for visited records are 0.00 and 1.00, respectively, confirming that all visited entries in the dataset are consistent with the definition of this feature. Conversely, for non-visited records, the mean and standard deviation are 0.00, as they exclusively represent months when no service occurred. This binary structure provides clear separation between the two groups and does not require a statistical p-value comparison. Instead, the feature effectively differentiates the dataset into two distinct segments for further analysis. Discount amounts are naturally higher for visited records since discounts are \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline  & \multicolumn{3}{c}{**Visited Records**} & \multicolumn{3}{c}{**Non-Visited Records**} \\ \hline
**Attribute** & **Mean** & \
\begin{tabular}{c} **Standard** \\ **Deviation** \\ \end{tabular} & **Median** & **Mean** &
\begin{tabular}{c} **Standard** \\ **Deviation** \\ \end{tabular} & **Median** & _p_-Value** \\ \hline Maintenance Period (year) & 11.32 & 8.62 & 16.00 & 10.71 & 8.60 & 16.00 & 0.00 \\ Days Between Service & 353.23 & 195.08 & 350 & 370.87 & 234.97 & 336 & 0.00 \\ Visits & 2.86 & 2.11 & 2.19 & 2.95 & 2.23 & 2.38 & 0.00 \\ Car Age (Years) & 2.86 & 2.11 & 2.19 & 2.95 & 2.23 & 2.38 & 0.00 \\ Remaining Guarantee & 129.87 & 181.80 & 0.00 & 137.23 & 201.30 & 0.00 & 0.00 \\ Days & 129.87 & 181.80 & 0.00 & 137.23 & 201.30 & 0.00 & 0.00 \\ Previous Total Net & 245.75 & 120.32 & 230 & 0.00 & 0.00 & 0.00 & 0.00 \\ Amount (EUR) & 20.15 & 15.22 & 15.00 & 0.00 & 0.00 & 0.00 & 0.00 \\ Mileage per Day (km) & 55.80 & 23.50 & 50.00 & 58.75 & 25.60 & 55.00 & 0.02 \\ Number of Service Visits & 3.25 & 1.20 & 3.00 & 1.00 & 0.00 & 1.00 & 0.00 \\ (User) & 1 & 0 & 1 & 0 & 0 & 0 & - \\ Cumulative Days Between & 1 & 0 & 1 & 0 & 0 & 0 & - \\ Service Visits & & & & & & & \\ Guarantee End Date & 2024.50 & 0.75 & 2024 & 2025.20 & 0.85 & 2025 & 0.01 \\ DSG Ratio & 0.12 & 0.05 & 0.10 & 0.08 & 0.03 & 0.07 & 0.00 \\ Cumulative Total Net & 800.75 & 350.20 & 750.00 & 0.00 & 0.00 & 0.00 & 0.00 \\ Amount (EUR) & & & & & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Statistical summary of visited records. only applied when a vehicle is serviced. Non-visited records have a consistent value of EUR 0, as no service occurred to warrant a discount. The data confirms this expected difference, and the \(p\)-value (\(\leq\)0.05) indicates that the disparity in mean discount amounts is statistically significant. Interestingly, non-visited records show a slightly higher mean for Mileage per Day (km). This could be attributed to vehicles that continue to accumulate mileage without visiting a service center. In contrast, visited records often reflect intervals when vehicles underwent maintenance, which may reduce the average daily usage temporarily. The \(p\)-value (\(\leq\)0.05) further validates that this difference is meaningful. Unsurprisingly, the mean Number of Service Visits (User) is much higher for visited records since these inherently represent actual maintenance events. On the other hand, non-visited records capture months with no service visits, which naturally lowers their mean value. The statistically significant \(p\)-value (\(\leq\)0.05) confirms this difference, aligning with the expected behavior of the dataset. For non-visited records, the Cumulative Days Between Service Visits is notably higher. This occurs because non-visited records continue to accumulate time gaps between maintenance events. Visited records, however, reset this duration after each service visit, leading to a comparatively lower cumulative value. The statistically significant \(p\)-value (\(\leq\)0.05) reinforces the significance of this observation.