Experience in post-crack performance testing of fiber-reinforced concrete (FRC) and shotcrete (FRS) using beams has demonstrated that variability both at first crack and in the post-crack range is high. When variability in performance is high it is important to carefully consider the within-set standard deviation in order to distinguish significant from insignificant differences between sets of data. It is also important to consider the characteristic distribution of results and use an appropriate probability distribution function (PDF) to estimate the standard deviation. The present investigation has sought to identify whether the Normal probability distribution function is the most appropriate model describing variability in cracking and post-crack performance parameters derived using beam tests.