표 4 / Table 4 청년층의 초기 2초 구간 삼킴 전후 비교 / The pre- & post-swallowing comparison in the first 2-sec. section in young adults

Variables	Swallowing		Mean(±SD)	t-value	p-value
F0	M	pre-	149.312(±25.22)	-0.45	.652
		post-	149.933(±25.12)
	F	pre-	275.412(±29.15)	0.71	.483
		post-	273.927(±27.37)
STD	pre-		1.615(±0.78)	-2.92	.005**
	post-		1.855(±0.91)
PER	pre-		483.850(±224.44)	-0.89	.376
	post-		499.400(±234.90)
Jitt	pre-		0.331(±0.19)	-0.80	.422
	post-		0.347(±0.15)
Jita	pre-		17.763(±12.37)	-0.64	.522
	post-		18.404(±10.23)
RAP	pre-		0.191(±0.12)	-0.47	.640
	post-		0.197(±0.09)
vF0	pre-		0.824(±0.41)	0.34	.061
	post-		0.960(±0.52)
ShdB	pre-		0.147(±0.07)	-0.77	.439
	post-		0.155(±0.06)
Shim	pre-		1.688(±0.88)	-0.83	.409
	post-		1.777(±0.77)
vAm	pre-		8.446(±3.92)	-0.68	.494
	post-		8.852(±4.65)
NHR	pre-		0.117(±0.01)	0.69	.489
	post-		0.116(±0.01)
VTI	pre-		0.040(±0.01)	0.10	.914
	post-		0.039(±0.01)

M, male; F, female; F0, average fundamental frequency; STD, standard deviation of F0; PER, pitch periods; Jitt, jitter percent; Jita, absolute jitter; RAP, relative average perturbation; vF0, F0 variation; ShdB, shimmer in dB; Shim, shimmer percent; vAm, peak amplitude variation; NHR, noise to harmonic ratio; VTI, voice turbulence index; SD, standard deviation. ^* p<.05, ^** p<.01, ^*** p<.001.