Appendix 4
Missed Signals for Individual Subjects
The following figures show the mean number of signals missed plotted against the signal luminance, for
each subject when viewing each combination of luminance and color used in the first and third
experiments. The y-axis error bars correspond to one standard deviation about the mean number of
signals missed. The x-axis error bars correspond to one standard deviation about the mean measured
luminance. The x-axis error bars are only given for the measurements made in the first experiment. This
is because for that study the luminance of the signals was measured in several different ways and the
results averaged. No additional luminance measurements were made in the third experiment, the
relationship between mean measured luminance and current through the LED established in the first
experiment being used to predict the current required to achieve the desired signal luminance in this
study.
A4-1