Experimental characteristics of the normalized standard deviation and confidence intervals of the quality factor (Q) of a mode-stirred reverberation chamber are compared with theoretical results. Fully empirical (model-free) statistics based on spectrally averaged S-parameter data show good agreement with semi-analytical estimates obtained from the theoretical Fisher-Snedecor distribution of Q with empirical distribution parameter M. For increasing frequency, the distribution of the boundaries of the sample confidence intervals rapidly tends toward Gauss normality. The location of the boundaries agrees closely with theory, while their spread reduces upon spectral averaging. Distributions and confidence intervals for the maximum and minimum Q are also obtained.