Thus, with a mean of 0.1449 and a variance of 0.1848, the variance of claim frequency exceeds its mean. In addition, the distribution of the independent variable, bonus-malus coefficient, shows that more than 50% of policyholders benefit from a bonus because they did not have any accidents declared. On one hand, it indicates a lack of homogeneity in the data, but on the other hand, it shows that the policyholders present a low risk for the insurance company. These results admit the assumption of heterogeneity and justify the a priori differentiation of policyholders.