Table 6.

Means, sample sizes (n), and standard deviations of participants’ characteristics and self-reported workload, together with the Pearson product-moment correlation coefficient with overall angular distance (n = 36)

	Mean	n	r	p
Gender (0: female / 1: male)	0.56	16 / 20	-0.09	0.619
Contact lenses (0: no / 1: yes)	0.22	28 / 8	0.16	0.341
Brown eyes (0: no / 1: yes)	0.39	22 / 14	0.19	0.276
Blue eyes (0: no / 1: yes)	0.14	31 / 5	0.23	0.172
Other eye color (0: no / 1: yes)	0.47	19 / 17	-0.34	0.040
	Mean	SD	r	p
Pupil diameter (mm)	3.80	0.66	0.06	0.732
TLX Mental demand (%)	28.5	20.4	-0.13	0.456
TLX Physical demand (%)	28.3	21.1	0.41	0.013
TLX Temporal demand (%)	18.3	17.1	0.46	0.005
TLX Performance (%)	29.2	21.1	0.09	0.598
TLX Effort (%)	35.8	22.3	0.32	0.056
TLX Frustration (%)	25.9	22.8	0.34	0.040

Scores for the NASA TLX were averaged across the two eye-trackers (only the Tobii 2 in two participants) and converted to a scale from 0% (minimum possible) to 100% (maximum possible). p < 0.05 is listed in boldface. For binary variables (gender, contact lenses, eye color), the Pearson product-moment correlation coefficient is equivalent to the point-biserial correlation coefficient. Other eye colors include hazel, gray, green, and amber