Table I.
Description and summary of sample
| Unweighted (% (N)) | Weighted (%) | SE (%) | |
|---|---|---|---|
| Birth cohort | |||
| 1975 – 1986 (18 – 29 yrs) | 37.7 (1 640) | 39.1 | 1.0 |
| 1965 – 1974 (30 – 39 yrs) | 24.5 (1 066) | 22.1 | 0.8 |
| 1955 – 1964 (40 – 49 yrs) | 17.7 (768) | 18.1 | 0.8 |
| 1912 – 1954 (≥50 yrs) | 20.2 (877) | 20.7 | 0.7 |
| Gender | |||
| Male | 39.8 (1 733) | 46.3 | 1.0 |
| Female | 60.2 (2 618) | 53.7 | 1.0 |
| Race | |||
| Black | 76.2 (3 317) | 76.2 | 0.2 |
| White | 12.9 (563) | 10.4 | 0.9 |
| Coloured | 7.2 (311) | 10.0 | 0.1 |
| Indian/Asian | 3.7 (160) | 3.4 | 0.4 |
| Education | |||
| None | 7.7 (326) | 6.8 | 0.5 |
| Grade 1 – 7 | 20.9 (886) | 19.1 | 0.9 |
| Grade 8 – 11 | 34.7 (1 471) | 35.4 | 1.0 |
| Matric | 22.2 (939) | 23.5 | 0.9 |
| Matric+ | 14.6 (618) | 15.3 | 1.0 |
| Marital status | |||
| Currently married | 49.7 (2 135) | 50.6 | <0.1 |
| Previously married | 8.0 (343) | 6.5 | <0.1 |
| Never married | 42.4 (1 820) | 42.9 | <0.1 |
| Employment | |||
| Employed | 30.0 (1 306) | 31.0 | 1.3 |
| Unemployed | 70.0 (3 045) | 69.0 | 1.3 |
| Income | |||
| Zero | 14.5 (629) | 13.7 | 0.8 |
| Low | 30.5 (1 329) | 29.5 | 1.1 |
| Low average | 15.7 (683) | 15.4 | 0.8 |
| High average | 19.1 (830) | 19.6 | 1.0 |
| High | 20.2 (880) | 21.8 | 0.9 |
| Rural/urban residence | |||
| Rural | 42.2 (1 836) | 38.4 | 1.0 |
| Urban | 57.8 (2 515) | 61.6 | 1.0 |
| Asset index | |||
| Low | 41.9 (1 822) | 39.3 | 1.3 |
| Medium | 37.3 (1 623) | 37.4 | 1.2 |
| High | 20.8 (906) | 23.3 | 1.3 |
| Drug use | |||
| Alcohol | 35.2 (1 532) | 38.7 | 1.2 |
| Tobacco | 26.9 (1 169) | 30.0 | 1.1 |
| Cannabis | 6.6 (288) | 8.4 | 0.6 |
| Other drugs (cocaine, etc.) | 1.4 (59) | 2.0 | 0.4 |
| Any extra-medical drug use | 19.6 (807) | 19.3 | 1.5 |
The SE of a method of measurement or estimation is the estimated SD of the error in that method. Namely, it is the SD of the difference between the measured or estimated values and the true values. Notice that the true value is, by definition, unknown and this implies that the SE of an estimate is itself an estimated value.