Table 4.

Exploratory factor analysis for the 3-factor solution of the PSQI-CZ. Factor analysis conducted using the maximum likelihood extraction method and oblimin rotation.

PSQI component	Sleep duration and efficiency	Sleep disturbances and quality	Sleep latency
Subjective sleep quality		0.63
Sleep latency			0.73
Sleep duration	0.99
Habitual sleep efficiency	0.45
Sleep disturbances		0.84
Sleep medication use			0.60
Daytime dysfunction		0.35
Variance explained	19.85%	19.54%	15.72%