Table 1.

Effect of CMV infection status, age and sex on the size of the CD28^null CD4 T-cell subset.^a

Variable	Parameter estimate	Standard error	95% CI for parameter		t	P-value	R2 b
			lower bound	upper bound
Intercept	-2.857	0.183	-3.218	-2.497	-15.614	0.000	47.8% c
Sex	0.020	0.069	-0.117	0.156	0.287	0.774
Age	0.004	0.002	7.168×10-5	0.008	2.005	0.046
CMV infection	1.012	0.070	0.874	1.149	14.499	0.000

^a The table shows the final step of the hierarchical multiple regression model.

^b Percent variability of dependent variable explained.

^c R² for models including sex alone or sex and age were 0.2 and 1.8%, respectively.