The mean differences between death age and predicted death age were analyzed in several ways. Deceased-umpire data analysis. Predicted death age is the life expectancy for each umpire at time of debut. Mean difference is calculated by subtracting the predicted death age from the mean death age. Those umpires who constitute the only unbiased sample are those for whom the entire cohort has already died.
Mean difference is calculated by subtracting mean predicted death age from death age.
Other abbreviations are the same as in Table 1. The set of umpires with at least one living cohort member, the next oldest group, was subjected to analysis. This analysis shows no significant difference from the life expectancy tables. Only length of career correlated with age at death. The analyses relied on data from full-time MLB umpires, and statistical inferences apply only to that population.