Table 2.
Steps for building final ANCOVA model for insomnia severity.
| F | df | p | η2 | Δη2 | |
|---|---|---|---|---|---|
| Basic ANOVA | 7.1 | 2,132 | .001*** | .10 | |
| Model 1-demographic variables added | .01 | ||||
| Age | 0.2 | 1,129 | .69 | .001 | |
| Gender | 1.0 | 1,129 | .32 | .008 | |
| Education | 0.1 | 1,129 | .81 | <.001 | |
| Group | 6.7 | 2,129 | .002** | .09 | |
| Model 2-health variables added | .03 | ||||
| Mini-Mental Status Exam | 0.1 | 1,126 | .77 | .001 | |
| Depressed mood (HAM-D factor) | 0.0 | 1,126 | .97 | <.001 | |
| Anxiety (HAM-D factor) | 0.5 | 1,126 | .47 | .004 | |
| Alcohol abuse in the past month (SCID-I/P) | 1.8 | 1,126 | .19 | .01 | |
| Physical illness burden (CIRS-G) | 2.3 | 1,126 | .13 | .02 | |
| Group | 5.1 | 2,126 | .008** | .07 | |
| Final model | .03 | ||||
| Physical illness burden (CIRS-G) | 2.4 | 1,129 | .12 | .02 | |
| Alcohol abuse in the past month (SCID-I/P) | 1.9 | 1,129 | .18 | .01 | |
| Group | 7.3 | 2,129 | .001** | .10 |
Note:
*
p <.05,
**
p <.01,
***
p <.001.
Δη2 = indicates difference compared to the basic ANOVA model, HAM-D=Hamilton Rating Score for Depression, SCID-I/P = The Clinical Interview for DSM-IV Axis I Disorders–Patient Edition, Version 2. CIRS-G = Cumulative Illness Rating Scale for Geriatrics.