Thanks for all comments and suggestions. They were all thoughtful and helpful.
I did a poor job of explaining the situation so a few people misinterpreted the information and thought I was referring to sideout percentage. The problem is that I never directly refer to serve quality, I only ever relate a serve to reception quality. I understand that is a complicated way of thinking about it.
To rephrase my point, after a positive (+) serve, the team in question was much more likely to win a point if the serve was a jump serve than if it was a float serve. For the record these are the actual figures.
The ‘winning’ suggestion was the observation that the float servers are most often middle blockers who then must defend. That is, the libero is not on court. Breaking down the above situation by whether or not the middle blocker is defending, we get the following figures for the float serve.
|Middle in defence||48||119||0.4034|
|Libero in defence||40||78||0.5128|
The sample isn’t really big, but it seems to show that there is a fairly large ‘libero effect’, at least with this team.
Oddly, for the ‘2’ reception, the ‘libero effect’ is much smaller and doesn’t explain the differences so well, but for the moment I am satisfied.