. Author manuscript; available in PMC: 2013 Apr 1.

Published in final edited form as: Cognit Ther Res. 2012 Apr;36(2):156–164. doi: 10.1007/s10608-011-9425-4

Table 2.

Hierarchical multiple regression predicting letter series (N = 72)

Variable	B	SE B	β	R²	ΔR²
Step 1	–	–	–	.12^*	.12^*
Age	−.24^**	.08^**	−.34^**	–	–
Education	.14	.26	.06	–	–
Complaint duration	−.00	.04	−.01	–	–
Step 2	–	–	–	.13	.01
Age	−.24^**	.08^**	−.35^**	–	–
Education	.12	.27	.05	–	–
Complaint duration	−.00	.04	−.01	–	–
TWT mean	−.01	.01	−.11	–	–
TST mean	−.01	.01	−.12	–	–
Step 3	–	–	–	.14	.01
Age	−.26^**	.09^**	−.37^**	–	–
Education	.11	.27	.05	–	–
Complaint duration	.00	.04	.01	–	–
TWT mean	−.01	.01	−.22	–	–
TST mean	−.01	.01	−.14	–	–
TWT variability	.03	.03	.17	–	–
TST variability	−.01	.02	−.06	–	–

TWT Total Wake Time, TST Total Sleep Time

P < .05,

^**

P < .01