Chapter 8 287 experiment by multiplying the failure probability after a given number of strokes by the number of fibers in a test tress. Figure 26 shows these models for the virgin and conditioned hair together with actual experimental results. Therefore, the reporting of Weibull parameters (together with the number of fibers in the tresses) allows anyone to recreate results for comparison and contrasting purposes. Figure 27 shows models and experimental data for virgin and bleached hair, and illustrates the higher incidence of breakage that occurs as the result of chemical damage. As possibly anticipated, the anti-breakage benefits of conditioning treatments are even more dramatic on this damaged hair. Furthermore, Figure 28 shows models and experimental data resulting from repeated grooming of virgin Caucasian hair as a function of the relative humidity, and demonstrates how findings from these experiments are in-line with predictions from the single fiber work. Some comments on the size of broken fiber fragments from repeated grooming experiments: Recalling principles that were Figure 26. Models and experimental data for repeated grooming experiments on virgin and conditioned Caucasian hair at 60% RH