## 4 Evaluation of Technical Condition of Vehicles at the PTI
The Influence of the Introduction of Quality Management System on the Results of PTI in Slovak Republic  
A research was carried out in the Slovak Republic in connection with the quality management system of PTIs. For this purpose, all PTIs of the Slovak Republic were divided into two groups, depending on the method of meeting the requirements for quality management (PTIs that have a quality management system introduced by a documented procedure (internal regulation) and PTIs that have implemented a quality management system according to STN EN ISO 9001). Subsequently, it was determined with what average percentage of temporary roadworthiness and not roadworthiness were the vehicles' technical condition for road traffic assessed by all PTIs that have a quality management system introduced by a documented procedure (internal regulation) (number: 137) and with what average percentage were assessed the technical condition of vehicles by all PTIs that have implemented a quality management system according to STN EN ISO 9001 (number: 21). The mentioned research was performed by means of data stored in the automated information system of technical inspections for the period of 2019 and 2020 [64]. The results are recorded in the Table 2.  
As the data in the Table 2 show, the PTIs that had a quality management system according to STN EN ISO 9001 assessed the technical condition of vehicles on average with a higher degree of temporary roadworthiness and not roadworthiness than PTIs that had a quality management system based on a documented procedure (internal regulation). At the same time, out of twenty one periodical technical inspection stations certified according to STN EN ISO 9001, sixteen of them (76%) have an established electronic booking system for customers who can use it to book an appointment for technical or emission inspection, which provides greater comfort for the customers. The significance of this difference can also be verified by statistical research. Based on statistical data on temporary roadworthiness and not roadworthiness of vehicles for road traffic, it is possible to establish the hypothesis (H1) that for the period of 2019-2020 in the Slovak Republic, the difference between the average percentage of temporarily roadworthy and not roadworthy vehicles of all PTIs which are certified according to ISO 9001 and PTIs without this certification is significant, against the hypothesis that this difference is not significant (Ho). So for this reason, statistical research will be carried out in the form of tests, performed on these two groups of values in the Data Analysis application in MS Excel program. One group shall represent the average results of the evaluation of PTI vehicles with ISO 9001 certification for the period 2019-2020, the other group shall represent the average results of the evaluation of PTI vehicles without ISO 9001 certification in the same period. Before performing the \(t\)-Test, an F-Test will be performed to compare the variance of the two groups of data, in order to select the correct \(t\)-Test. The results of the F-Test are shown in the Table 3. \begin{table}
\begin{tabular}{c c c} \hline \hline  & **The Average Rate of Assessment of** & **The Average Rate of Assessment of** \\  & **Temporary Roadworthiness and** & **Temporary Roadworthiness and Not** \\  & **Not Roadworthiness of Vehicles for** & **Roadworthiness of Vehicles for Road** \\
**Year** & **Road Traffic Use, Assessed by the** & **Traffic Use, Assessed by the PTI,** \\  & **PTI, Which Fulfil the Minimum** & **Which Fulfil the Minimum** \\  & **Requirements for Quality** & **Requirements for Quality** \\  & **Management by a Documented** & **Management According to** \\  & **Procedure (Internal Regulation)** & **STN EN ISO 9001** \\ \hline
2019 & 12.52\% & 14.17\% \\
2020 & 12.84\% & 14.57\% \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Results of the evaluation of vehicles at PTI depending on the method of meeting the requirements for quality management; Source: Author according to [65].