Table 2.

Term frequency–inverse document frequency of selected keywords.

Number and themes		Term frequency–inverse document frequency = (Term frequency × Inverse document frequency)	Term frequency	Inverse document frequency
1
	Question	590.3	150.0	3.9
	Answer	199.8	38.0	5.3
2
	Hospital	660.6	173.0	3.8
	Clinic	46.5	7.0	6.6
3
	Market	55.7	9.0	6.2
	Company	471.2	112.0	4.2
4
	Doctor	458.6	106.0	4.3
	Nurse	340.0	73.0	4.7
5
	Family	28.8	4.0	7.2
	Patient	203.7	39.0	5.2
6
	iPad	331.4	74.0	4.5
	Tablet	433.4	103.0	4.2
7
	System	397.7	91.0	4.4
	App	84.3	14.0	6.0
8
	Security	103.6	18.0	5.8
	Caregiving	305.7	68.0	4.5