Table 4.

Posterior predictive simulation check.

Variable	p	adjusted p	Posterior predictive p-value
STD HR (bpm)	0.0000133	0.000707	0.012
STD RRI (ms)	0.0000366	0.00194	0.00599
SD2 (ms)	0.0000423	0.00224	0.00899
TINN (ms)	0.0001	0.00532	0.0959
Double product (bpm⋅mmHg)	0.000122	0.00649	0.457
RMSSD (ms)	0.000194	0.0103	0.161
SD1 (ms)	0.000194	0.0103	0.174
D2	0.000204	0.0108	0.9
MBP (mmHg)	0.000313	0.0166	0.465
LFpw (ms2)	0.000385	0.0204	0.015
TP (ms2)	0.000396	0.021	0.000999
SBP (mmHg)	0.000514	0.0273	0.236
RRI triangular index	0.000689	0.0365	0.271

The prediction of the mental workload from cardiovascular variables was assessed by the posterior predictive p-value. The highest p-value indicates the most predictive variable (bold). All cardiovascular variables were first tested for the period factor fixed effect, and only significant variables are sorted by increasing p-values. STD HR, standard deviation of HR; STD RRI, standard deviation of RRI; SD2, semi-major axis of Poincaré plot ellipse fitting; TINN, triangular interpolation of RRI histogram; RMSSD, root mean square of successive differences; SD1, standard deviation of the instantaneous beat-to-beat inter-beat interval variability (semi-minor axis length of Poincaré plot ellipse fitting); D2, correlation dimension; MBP, mean blood pressure; LFpw, low frequency power; TP, total power; SBP, systolic blood pressure.