This could be a result of their small number of specimens and the variability of sacral gradient in vivo compared with the cadaveric study.
This lack of correlation between oestrogen responsive cDNAs in MCF-7 cells and carcinoma specimens, and the variability of patterns of gene expression in breast carcinomas has recently also been reported using array technology (Gruvberger et al, 2001).
In any case, the issue of specimen-to-specimen variability, compounded by a relatively small sample size, is a common problem in biomechanical studies [26, 30, 34, 37, 38, 42].
The fragility functions developed in this paper incorporate uncertainty arising from specimen-to-specimen variability as well as statistical uncertainty associated with the fact of being developed based on a small sample of experimental results.
In this case of a single test, the variability between specimens was not captured in the measurement error, and the proposed correlation model provides a physical basis for approximating the specimen variability.
Furthermore, it is difficult to compare our presented data with other studies due to different evaluated parameters and the variability of specimens, their dimensions, the presence of metallic implants, and the design of the implants.
These probabilistic models require not only a good understanding of the variability in specimen data, but also an understanding of the microstructural sources of variability to allow scaling to component analysis.
However, one advantage of using a single specimen is that it reduces the variability between different samples.
The study design did not allow for determination of the intra- and inter-observer variability of the methods; however, the variability between the three specimens from each specimen was determined to be good (R = 0.684).
Additionally, the variability among Hapalops specimens studied here is less than what is considered intraspecific variation among anatomical characters in a single living species.
