Descriptive statistics for height standardised lung function for 30–35 year old workers, and the lower limits of normal, and % rejected for the predicted and selected reference equations
| Lung function | Mean | SD | Skewness | Lower 95% CI | Lower limit of normal; % rejected for the different equations | |||
| Black miners, n=4503, age=32.6 (SD 1.7), height=1.7: | Predicted | Louw | ECCS | |||||
| FVC (l) | 4.21 | 0.51 | 0.14 | 3.37 | 3.34; 4.4% | 3.44; 6.6% | 3.68; 14.9% | |
| FEV1(l) | 3.60 | 0.46 | −0.03 | 2.84 | 2.81; 4.3% | 2.78; 3.8% | 3.07; 12.5% | |
| FEV1% | 85.6 | 6.11 | −0.74 | 75.5 | 74.7; 3.8% | NA | 71.7; 1.2% | |
| White miners, n=620, age=32.7 (SD 1.7), height=1.8: | Predicted | Knudson | ECCS | |||||
| FVC (l) | 4.54 | 0.53 | 0.15 | 3.66 | 3.62; 4.09% | 3.54; 3.0% | 3.68; 5.3% | |
| FEV1(l) | 3.74 | 0.45 | −0.01 | 3.01 | 2.96; 4.9% | 2.98; 4.6% | 3.06; 6.6% | |
| FEV1% | 82.5 | 5.8 | −0.27 | 73.0 | 72.7; 4.6% | 73.0; 5.1% | 71.7; 3.1% | |