The sexual behavior scores of three different groups of DBA/2J male mice, run at different times of the year, in two different places, and by different observers, were compared. Of 46 comparisons, two revealed statistically significant differences. It was hypothesized that one measure (% Move) was subject to much environmentally determined variation, while for the other measure (III), the significant difference may have been due to sampling error.

Furthermore, substitution of the data resulting from either replication for the data of the DBA/2J males of the original study did not result in any changes as regards significant differences in sexual behavior among DBA/2J, C57BL, and BALB/c male mice. The results, in general, supported the hypothesis that intensive study of a small sample from an inbred strain would yield replicable results.