Table 5. Investigation of EMF exposure from sources other than HVT lines.

sources	Students in School A		Students in School B		χ2	p-value
	n a)	% b)	n c)	% d)
High-tension lines surrounding residence
Yes	98	47.57	114	52.05	0.853	0.356
No	108	52.43	105	47.95
Transformer or transformer substation surrounding residence
Yes	49	23.90	52	23.85	<0.001	0.991
No	156	76.10	166	76.15
Transformer or transformer substation from residence to school
Yes	60	29.56	64	28.96	0.018	0.893
No	143	70.44	157	71.04
Frequent use of household appliances e)
Yes	85	42.08	90	42.65	0.014	0.906
No	117	57.92	121	57.35
Frequent use of computers
Yes	88	43.14	116	52.49	3.717	0.054
No	116	56.86	105	47.51
Frequent use of TVs
Yes	147	72.41	135	62.50	4.674	0.031*
No	56	27.59	81	37.50
Frequent use of mobile phones
Yes	47	23.50	44	20.47	0.557	0.455
No	153	76.50	171	79.53
Frequent use of fixed-line telephone
Yes	52	25.87	32	15.09	7.395	0.007*
No	149	74.13	180	84.91
Bed located near air conditioner or refrigerator
Yes	27	13.30	36	16.59	0.890	0.345
No	176	96.70	181	83.41

^a)Dada may not sum up to n = 206 in School A due to non-response.

^c)Dada may not sum up to n = 221 in School B due to non-response.

^b)and ^d) Dada sum up to 100% due to calculation not included non-response.

^e)It was defined as the use of one or more of the household appliances, namely computers, TVs, mobile phones and fixed-line telephone in daily life.

^*Compared with students in School A, P<0.05.