Table 1. Demographic characteristics and their association coefficients of 348 respondents from the University of Medicine and Pharmacy, Ho Chi Minh City, Vietnam in the phantom vibration survey 2014-2015
| Characteristics | No (%) of respondents | Chi2 p-value |
| Total (% of column) | With PV (% of row) |
| Sex | | 348 (100) | | 0.767 |
| Male | 185(53.1) | 141(76.22) |
| Female | 163(46.9) | 122(74.85) |
| School year | | 346(100) | | 0.544 |
| Sixth | 53(15.3) | 42(79.25) |
| Fifth | 71(20.5) | 59(83.1) |
| Fourth | 36(10.4) | 26(72.2) |
| Third | 68(19.65) | 51(75) |
| Second | 73(21.1) | 52(71.2) |
| First | 45(13.2) | 32(71.1) |
| Age | | 348(100) | | 0.528* |
| 28 | 1(0.3) | 1(100) |
| 27 | 1(0.3) | 0(0) |
| 26 | 13(3.7) | 10(76.9) |
| 25 | 55(15.8) | 45(81.8) |
| 24 | 60(17.2) | 48(80.0) |
| 23 | 51(14.7) | 40(78.4) |
| 22 | 61(17.5) | 44(72.1) |
| 21 | 72(20.7) | 52(72.2) |
| 20 | 34(9.8) | 23(67.65) |
Fisher’s test p-value