# A Study on Ergonomic Layout of Automotive Electronic Shift Buttons
## 2 Methods
### Data Analyses  
The methods for analyzing the results corresponding to each of the four research activities to address the two research questions of this study were as follows. The two research questions were (1) \"What constitutes an ergonomic electronic shift button layout?\" **(Research question 1)** and (2) \"How does the ergonomic performance of electronic shift button layouts vary depending on driving experience?\" **(Research question 2)**. 6.1 Research Activity 1-1) Identify Excellent Shift Button Layouts that Receive High Marks from All Respondents (Regardless of Driving Experience)  
A one-way repeated-measures analysis of variance (ANOVA) was conducted to test the impact of the independent variable (layout) on each dependent variable (accuracy, convenience, rapidity, learnability, intuitiveness, safety, and preference). [PERSON]'s test was performed to assess the sphericity of the data for each ANOVA test. In cases wherein the sphericity was violated, the degrees of freedom were corrected; the Greenhouse-Geisser correction was used when the Greenhouse-Geisser estimate of sphericity (\(\epsilon\)) was less than 0.75; otherwise, the Huynh-Feldt correction was used [26; 27]. In the case of statistically significant ANOVA results, post-hoc multiple comparisons with Bonferroni corrections were conducted to determine the pairs of button layouts that significantly differed in terms of the mean value. \begin{table}
\begin{tabular}{p{142.3 pt} p{284.5 pt}} \hline \hline
**Measure** & **Question** \\ \hline
**Accuracy** & This layout will help me shift gears accurately without error. \\ \hline
**Convenience** & This layout will help me shift gears conveniently in terms of gaze behavior or manipulation. \\ \hline
**Rapidity** & This layout will help me shift gears quickly. \\ \hline
**Learnability** & This layout can be adopted easily and used without much effort or learning. \\ \hline
**Intuitiveness** & The arrangement and order of buttons in this layout meet my expectations. \\ \hline
**Safety** & This layout will help me drive safely. \\ \hline
**Preference** & I like this layout (I’m willing to use/buy it). \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Seven subjective rating measures and corresponding questions. 6.2 Research Activity 1-2) Determine Principles that Should Be Considered when Designing Shift Button Layouts  
A paired \(t\)-test was conducted to study the impact of the independent variable (ergonomic principle) on each dependent variable (accuracy, convenience, rapidity, learnability, intuitiveness, safety, and preference). The pairs of layouts that were compared to study the effectiveness of applying each ergonomic principle are provided in Table 4.  
6.3 Research Activity 2-1) Identify Excellent Shift Button Layouts that Receive High Scores from Each Driving Experience Group (Driving for \(\leq\)2 Years or \(>\)2 Years)  
Two-way mixed ANOVA was conducted to test the main and interaction effects of the independent variables (layout and driving experience) on each dependent variable (accuracy, convenience, rapidity, learnability, intuitiveness, safety, and preference). The simple main effects for each independent variable in the case where there was a significant interaction effect between the independent variables were investigated. 6.4 Research Activity 2-2) Determine Principles that Should Be Considered when Designing Shift Button Layouts for Each Driving Experience Group  
A two-way mixed ANOVA was conducted to test the main and interaction effects of the independent variables (ergonomic principle and driving experience) on each dependent variable (accuracy, convenience, rapidity, learnability, intuitiveness, safety, and preference). In the case where there was a significant interaction effect between the independent variables, simple main effects for each independent variable were investigated. The pairs of layouts in Table 6 were again used here to examine the effectiveness of applying each ergonomic principle.