This knitted rmarkdown document aims to provide a succinct methodological explanation on estimating the average adult size of T. rex based on femoral dimensions. Mean femur length for the 33 adult T. rex specimens from a previously compiled dataset (Paul et al. 2022) is 1230 mm (90% CI 1203-1249 mm), mean femur circumference is 521 mm (90% CI 509-533 mm) and mean body mass based on said circumference (cQE, Campione et al. 2014) is 6.3 t (90% CI 6.0-6.8 t). These figures highlight the availability of a sufficiently large sample of specimens to constrain average size of T. rex with a fair degree of confidence, and therefore negates oft-proclaimed arguments for a reliance on statistically biased and arbitrary specimen-to-specimen comparisons between T. rex and other animals in discussions of their relative sizes. A larger source of error than statistical uncertainty resulting from the limited sample size is undoubtedly the deviation between different mass estimates (with volumetric figures for a single specimen potentially diverging up to 2 tons). However, the impact of this issue is mitigated by a reliance on averages drawn from a larger sample.
2025 update