Bias properties of extragalactic distance indicators. VIII. H-0 from distance-limited luminosity class and morphological type-specific luminosity functions for Sb, Sbc and Sc galaxies calibrated using Cepheids

Relative, reduced to absolute, magnitude distributions are obtained for Sb, Sbc, and Sc galaxies in the flux-limited Revised Shapley-Ames Catalog (RSA 2) for each van den Bergh luminosity class (L), within each Hubble type (T) . The method to isolate bias-free subsets of the total sample is via Spaenh auer diagrams, as in previous papers of this series. The distance-limited t ype and class-specific luminosity functions are normalized to numbers of ga laxies per unit volume (10(5) Mpc(3)), rather than being left as relative f unctions, as in Paper V. The functions are calculated using kinematic absol ute magnitudes, based on an arbitrary trial value of H-0 = 50. Gaussian fit s to the individual normalized functions are listed for each T and L subcla ss. As in Paper V, the data can be freed from the T and L dependencies by a pplying a correction of 0.23T + 0.5L to the individual absolute magnitudes. Here, T = 3 for Sb, 4 for Sbc, and 5 for Sc galaxies, and the L values ran ge from 1 to 6 as the luminosity class changes from I to III-IV. The total luminosity function, obtained by combining the volume-normalized Sb, Sbc, a nd Sc individual luminosity functions, each corrected for the T and L depen dencies, has an rms dispersion of 0.67 mag, similar to much of the Tully-Fi sher parameter space. Absolute calibration of the trial kinematic absolute magnitudes is made usi ng 27 galaxies with known T and L that also have Cepheid distances. This pe rmits the systematic correction to the H-0 = 50 kinematic absolute magnitud es of 0.22 +/- 0.12 mag, giving H-0 = 55 +/- 3 (internal) km s(-1) Mpc(-1). The Cepheid distances are based on the Madore/Freedman Cepheid period-lumin osity (PL) zero point that requires (m - M)(0) = 18.50 for the LMC. Using t he modern LMC modulus of (m - M)(0) = 18.58 requires a 4% decrease in H-0, giving a final value of H-0 = 53 +/- 7 (external) by this method. These val ues of H-0, based here on the method of luminosity functions, are in good a greement with (1) H-0 = 55 +/- 5 by Theureau and coworkers from their bias- corrected Tully-Fisher method of "normalized distances" for field galaxies; (2) H-0 = 56 +/- 4 from the method through the Virgo Cluster, as corrected to the global kinematic frame (Tammann and coworkers); and (3) H-0 = 58 +/ - 5 from Cepheid-calibrated Type Ia supernovae (Saha and coworkers). Our va lue here also disagrees with the final value from the NASA "Key Project" gr oup value of H-0 = 70 +/- 7. Analysis of the total flux-limited sample of Sb, Sbc, and Sc galaxies in th e RSA2 by the present method, but uncorrected for selection bias, would giv e an incorrect value of H-0 = 71 using the same Cepheid calibration. The ef fect of the bias is pernicious at the 30% level; either it must be correcte d by the methods in the papers of this series, or the data must be restrict ed to the distance-limited subset of any sample, as is done here.