TABLE 3.

Single model standard errors of prediction for area-normalized spectra

	RMS	Cross-valid lin	Direct valid	Frequencies in model	Model →% of the secondary structure
α-Helix	21.8	6.3	5.8	–	−218.813 + 2.473 × A1545 + 0.565 × A1655 + 1.121 × A1611
β-Sheet	17.6	7.6	7.0	1545–1655–1611	134.940 + 0.3861 × A1545 − 0.859 × A1655 − 0.741 × A1611
β-Turns	4.2	3.6	3.2	–	−14.043 + 0.475 × A1545 + 0.380 × A1655 − 0.650 × A1611
Random	11.4	8.9	7.9	–	216.0146 − 1.285 × A1545 − 0.457 × (A1655) − 1.019 × A1611

For legend, see Table 1. A linear model was used for either direct or cross-validations. The standard error of prediction has been minimized for the four structures together, yielding the same three wavenumbers for all the models.