Abstract This investigation analyzed the uncertainty of compression resistance in the average statistics, standard error, asymmetry, kurtosis and confidence intervals taking into account the Bootstrap method. The implementation of the Bootstrap method in determining the physical properties of the material used in the construction of buildings, is a fundamental tool to establish the physical behavior of existing buildings. The application of the Bootstrap method allowed estimating the statistics for the reported dosages with different samples; 1:2:2, allowing to estimate statistics. The results allowed to determine the probability density function of the average value of the compressive strength and with it, probabilistic resistance values can be established. This research determined statistical results of the compressive strength vital to carry out revision, vulnerability and structural reinforcement studies of existing buildings in the municipality of Ocaña, Colombia.