How would you calculate the order of a list of reviews sorted by "Most Helpful" to "Least Helpful"?


Here's an example inspired by product reviews on Amazon:


Say a product has 8 total reviews and they are sorted by "Most Helpful" to "Least Helpful" based on the part that says "x of y people found this review helpful".


Here is how the reviews are sorted starting with "Most Helpful" and ending with "Least Helpful":


7 of 7  

21 of 26  

9 of 10  

6 of 6  

8 of 9  

5 of 5  

7 of 8  

12 of 15


What equation do I need to use to calculate this sort order correctly? I thought I had it a few times but the "7 of 7" and "6 of 6" and "5 of 5" always throw me off. What am I missing?



Calculating the "Most Helpful" review
See [How not to sort by average ranking](http://www.evanmiller.org/how-not-to-sort-by-average-rating.html).


