Cumulative distributions of the spectral types of BeXRBs populations in the SMC for our sample (solid blue, excluding source CH6-20) compared with the samples (dashed green) of Antoniou et al. (2009b) and McBride et al. (2008). By applying the Kolmogorov–Smirnov test, we find that our sample is different from the previous ones, at more than 99 per cent confidence level (the probability to reject the null hypothesis, that the two distributions come from the same parent distribution, is given above each plot). This indicates that our sample is skewed to later spectral types.