Evaluating normality of procedure up--down trasformed response by Kolmogorov--Smirnov test applied to difference thresholds for seat vibration

Drivers and passengers appreciate the vibration of vehicles. Their subjective rating of discomfort may affect their opinion of the vehicle. This study investigated the difference threshold required for a change in vehicle ride to be perceived. We propose the Kolmogorov--Smirnov (K--S) test to decide if the sample comes from a population with a specific distribution and to evaluate the variability of the data.