APPROXIMATE CONFIDENCE-INTERVALS FOR HERITABILITY FROM METHOD-R ESTIMATES

Method R estimates of heritability (h(2)) and associated confidence in tervals (CI) were obtained from simulated data using a single trait, d irect effects, full animal model, with 50% subsampling. Five hundred d ata sets were simulated for each of five levels of h(2) (.10, .20, .30 , .40, and .50) and two types of pedigree structure (random pedigree s tructure [N = 2,000] that varied over simulations, or the pedigree str ucture from a real data set [N = 2,644] that was constant for all simu lations). The first 10, 20, and all 50 h(2) estimates were used to obt ain 80, 90, 95, and 99% CI for each data set. The variance of h(2) est imates within data sets approximated the sampling variance of the h(2) estimates. The Box-Cox transformation was used to normalize the distr ibution of estimates from each data set. Confidence intervals were com puted on the transformed scale as CI = mu +/- (T x sigma), where mu an d sigma = the mean and SD of the N transformed h(2) estimates, respect ively, and T = the critical value from the T distribution for a 1 - al pha CI, with df = N - 1. Upper and lower CI bounds were converted back to the original scale by reversing the transformation. The percentage s of CI containing the true h(2) value, pooled across all levels of h( 2), types of pedigree, and number of estimates used to obtain CI, for 80, 90, 95, and 99% CI were 81.14, 90.96, 95.27, and 98.76%, respectiv ely. These results suggested that Method R h(2) estimates can be used to obtain reliable CI.