Table 2. One-way ANOVA analysis of the PC1 values for the correctly classified subjects and Student's t-test for detecting statistically significant differences.

Sub- population	No. of subjects	Mean PC1	s.d.	s.e.	Lower 99.9% CL	Upper 99.9% CL	Difference of the PC1 mean values	Lower 99.9% CL difference	Upper 99.9% CL difference	P-value
(A)
HNC	16	2.59	1.17	0.29	1.20	4.00	4.20	2.58	5.81	<0.0001
Healthy	26	−1.59	1.77	0.35	−2.70	−0.50
(B)
LC	20	3.13	1.13	0.25	2.15	4.11	5.53	4.00	7.08	<0.0001
Healthy	26	−2.41	1.82	0.36	−3.74	−1.08
(C)
HNC	16	2.20	0.34	0.08	1.86	2.55	3.97	5.45	2.48	<0.0001
LC	20	−1.76	1.69	0.38	−3.23	−0.29
(D)
HNC	16	2.92	1.93	0.48	0.96	4.89
LC	20	1.25	3.48	0.78	−1.77	4.28
Healthy	26	−2.76	2.13	0.42	−4.32	−1.21

Abbreviations: ANOVA=analysis of variance; PC1=first principal component.

Mean value of PC1, s.d., as well as upper and lower 99.9% confidence limit (CL), differences in PC1 values and CLs, and P-values for (A) healthy controls and head-and-neck cancer (HNC) patients, (B) healthy controls and lung cancer (LC) patients, (C) HNC and LC patients, and (D) healthy controls, LC and HNC patients.