Comparison between the model spectrum obtained by the average over the loop lengths (black) and the observed spectrum (red) for the solar activity minimum. The left side compares the averages in bins equally divided in linear scale, while the right side compares the averages in bins equally divided in logarithmic scale (bin size defined as in Fig. 3). The top panels display the averaged model spectrum weighted by the power-law distribution, and the bottom panels display the averaged model spectrum weighted by the chi-squared distribution.