Model fitting and cross-validation results for scaled CT radiodensity histogram (scanner 2)
| CT Histogram | ||||||
|---|---|---|---|---|---|---|
| Mean (k = 2) | Mode (k = 2) | FWHM (k = 1) | Skewness (log [age]), (k = 1) | Kurtosis (k = 2) | σ (k = 1) | |
| Polynomial (age, k) | ||||||
| R2 | 0.77 | 0.80 | 0.22 | 0.70 | 0.54 | 0.068 |
| RMSE | 0.87 | 0.85 | 1.16 | 0.14 | 0.35 | 0.34 |
| β0 | 28.6 | 28.7 | 12.7 | 0.68 | 3.7 | 6.3 |
| β1 | 10.2 | 10.5 | 4.4 | −0.12 | −2.3 | 0.65 |
| β2 | −5.3 | −6.4 | – | – | 1.3 | – |
| Cross-validation (LOOCV) | ||||||
| RMSE | 0.93 | 0.91 | 1.20 | 0.15 | 0.36 | 0.35 |
| RMSE increase | 6.9% | 7.1% | 3.4% | 7.1% | 5.3% | 3.6% |
Note:— k indicates order/degree of the polynomial.