# Comparing the standard deviation of movie ratings

I have 2 movies, their rating distribution is this:

movie_id 1_star 2_star  3_star  4_star  5_star  std
1        0.661  0.231   0.081   0.012   0.015   1.629
2        0.002  0.005   0.071   0.314   0.608   1.335


1~5 star corresponding to the rating as 2~10

If we look at the distribution, these 2 would look like

The question is that, which one would have a higher deviation in the rating?

While the first movie's rating looks more clustered, but it turns out that it has a higher standard deviation.

What is happening?

My analysis is that, notice the tail distribution, the movie 1 has 1.4% with 5 star, while movie 2 only has 0.2%.

But I'm not sure if this is the reason? or there are other reasons?

• Yes, that's the same calculation that I've done. but it's a bit counter-intuitive that such a tiny portion of high rating would affect the std dramatically. Is there any good/detailed explanation? – cqcn1991 May 23 '17 at 10:34
• And is there any alternative than the std to describe the extent of how data clustering together? I think std is standard and there is no other good way to do it? – cqcn1991 May 23 '17 at 10:46