## 3 Results and Discussion
### Effect of IC Design
#### 3.4.2 Reading Errors  
A summary of reading errors for individual ICs is presented in Table 4. As can be seen from Tables 3 and 4 in Appendix A, a number of coarse errors occurred, which are detailed in Table 4. Coarse errors are values that are far from the set speed, e.g., errors not caused by the scale graduation. Because of these large deviations from the set values, the results are described and analyzed by the median and range instead of the mean value and standard deviation of the reading error [2,31]. Ratios of the number of coarse errors to the number of correct values are also considered in evaluating the differences between the ICs and their speedometers. The lowest reading errors were achieved in the 2 nd session on IC06. No coarse errors were noted on both classical-style IC02 and IC04, and the error range was relatively low. The highest ratio of coarse errors was recorded on IC01 (analog speedometer) and IC07 (digital speedometer). The values read by the participants correspond to the values set on the tachometer. The exceptions are two readings on IC06 (25 and 52 km/h instead of 40 km/h) and one reading on IC07 (250 km/h instead of 46 km/h), all in the 1 st session. The mean RT in the cases where most of the coarse errors were recorded was 2527 ms on IC01 and 4120 ms on IC07. \begin{table}
\begin{tabular}{c c c c c c c c} \hline
**Session 1** & **IC** & **01** & **02** & **03** & **04** & **05** & **06** & **07** \\ \hline \(v_{s}\), km/h & 55 & 47 & 52 & 58 & 54 & 40 & 46 \\ error magnitude median & 2.0 & 2.0 & 1.0 & 1.0 & 0.0 & 0.0 & 0.0 \\ error maximum positive & 5 & 13 & 3 & 2 & 4 & 12 & 204 \\ error maximum negative & \(-42\) & \(-2\) & \(-37\) & \(-10\) & \(-19\) & \(-15\) & \(-33\) \\ error absolute range & 47 & 15 & 40 & 12 & 23 & 27 & 237 \\ no. of exact readings & 12 & 1 & 15 & 12 & 21 & 30 & 26 \\ no. of coarse errors & 7 & 0 & 1 & 0 & 1 & 1 & 6 \\ \hline
**Session 2** & **IC** & **01** & **02** & **03** & **04** & **05** & **06** & **07** \\ \hline \(v_{s}\), km/h & 121 & 85 & 159 & 162 & 93 & 82 & 104 \\ error magnitude median & 11.0 & 2.5 & 1.0 & 1.0 & 0.5 & 0.0 & 0.0 \\ error maximum positive & 9 & 5 & 21 & 8 & 5 & 0 & 6 \\ error maximum negative & \(-91\) & \(-5\) & \(-29 Three participants repeated coarse errors in the 2 nd session on IC01 (participants no. 4, 22, and 24), and the other three participants repeated coarse errors in the 2 nd session on IC07 (no. 9, 28, and 32). Two participants had three coarse errors in the first session (no. 4 and 11), and the other two had two coarse errors in the first session (no. 28 and 32). In the second session, only one participant had two coarse errors (no. 12). Both IC01 and IC07 have a tachometer shaped and sized like a speedometer, graduated in hundreds of revolutions per minute (RPM), i.e., 10, 20, 30, etc. This apparently led to confusion between a speedometer and a tachometer. The tachometer on IC04 was also graded in hundreds of RPM, but the larger size of the speedometer than the tachometer contributed to the reading from the correct instrument. IC01 and IC02 have similar (classic) designs, but IC02 has a tachometer graduated in thousands of RPM (i.e., 1, 2, 3, etc). The tachometer reading on IC02 (coarse errors) was not recorded, as it was on IC01, despite the similarity of the IC layout. IC05 has both digital and analog speed presentation, but the wrong readings from the second round instrument (power status indicator) were noted in both sessions. While the research of [PERSON] et al. [20] showed that a redundant speedometer (combined analog and digital representation) had the best performance compared to the analog or digital, this was not the case in this experiment. Although the digital presentation of the speed is unambiguous, and the digits are several times bigger than the digits on the classic speedometer scale, mistakes did happen. Coarse errors have already been explained by the confusion with another instrument.