Table 2.

Comparisons of baseline values between those with (n = 1,652) and without (n = 1,313) valid answers at both baseline and follow-up on the Circadian Type Inventory-revised (CTI-r) on age, sex, languidity, flexibility, child care status, marital status, night work status, and the insomnia score on the Bergen Insomnia Scale (BIS).

Variable	Valid answers at both baseline and follow-up [% or mean (SD)]	Not valid answers at both baseline and follow-up [% or mean (SD)]	χ2/df or t/df	p
Age	31.9 (8.4)	31.7 (8.0)	t/2954 = −0.65	0.516
Sex	90.9%♀	90.4%♀	χ2/1 = 0.17	0.684
Languidity	20.6 (3.7)	20.7 (3.8)	t/2853 = 0.35	0.729
Flexibility	12.5 (4.1)	12.4 (4.1)	t/2865 = −0.18	0.858
Child care status	Children at home 41.5%	Children at home 46.8%	χ2/1 = 7.68	0.006
Marital status	In relationship 67.6%	In relationship 73.0%	χ2/1 = 10.62	0.002
Night work status	Have night work 64.0%	Have night work 64.9%	χ2/1 = 0.18	0.668
Insomnia score	12.6 (8.1)	13.9 (8.4)	t/2907 = 4.37	<0.001