Dude I'm a mathematician and for one thing your graphs need there x- and y-axes labelled. Otherwise the numbers become a little meaningless. Next with histograms what matters is not the curve (sine curve?
) but the spread of frequencies and how they are distributed.
The histogram can be divided in two partitions; the left part being the poor and average episodes, which are slightly more numerous than the right part being the good and excellent episodes.
The bottom line: the spread is skewed to the average episodes, and the median (middle; half of the cumulative frequency 19) would be somewhere around the ranking 4.
Conclusion: from the histogram, and taking the median, the first season of DS9 is somewhat below average.