Interesting, I suppose  horror movies are often works only once or twice,  till it got overused just to keep the hype going.  As for star trek, well in my opinion you can't really go wrong with them. I wondering what the data will be like for chuckie??

I think the main point is how many of the movies get over 49%. I picked this number because I wanted a low bar without giving it away.

I notice that with the horror movies, the first movie does well and the franchise is carried by that.

Oooh, interesting indeed - it certainly seems that the above horror franchises tend to have awful sequels (whilst Star Trek has a bad first showing, but was presumably brought to the big screen for a second time on the strength of the TV series alone.) 

I'd be a bit wary of using Star Trek as a comparison - certainly the last three were huge budget affairs, and whilst that alone won't make a movie it does allow a great deal of polish that I would expect reviewers to appreciate. Perhaps a scoring relative to other films released that year on a similar budget would allow a better like-for-like comparison, although I'm not sure how you'd measure how 'niche' a film is; horror films don't have the same wide appeal as, say, family or comedy films.

Still, I suspect that your hypothesis does have some truth in it (although I would phrase it in terms of the difficulty in making a 'good' horror film compared to other genres.) That and the point made above about a series of horror films losing the initial unknown aspect that makes for good horror.