CASE STUDIES IN BIOMETRY: Chapter 8. Mixture Fraction and Linkage Analyses for Hybrid Onions Dennis L. Clason, Joe Corgan, Catherine M. Cryder, N. Scott Urquhart The file ch8.dat contains the following variables: Pop - population code, 1034 or 1040 ADH - 1 (cepa), 2 (het) or 3 (fist) IDH - 1 (cepa), 2 (het) or 3 (fist) PGI - 1 (cepa), 2 (het) or 3 (fist) freq - frequency