2.3. Sample Size
Data on the driving ability measurements of local older adults conducted in the past at driving schools and automobile driving tests were used as reference materials. The sample size was calculated considering a 5-point change in driving skill assessment scores post-intervention, an 8-point standard deviation of the difference, 80% power, and a 5% significance level. A 10% dropout rate was adopted based on previous intervention studies. Finally, 74 participants were included in this study.