>If the data says "C is better than Ada" but it's 50% confidence,
>doesn't that mean there's a 50% chance Ada is better than C ?
  The usual null hypothesis is "no difference", so 50% confidence
would mean "C may be better than Ada, or it may not be any better,
and the data are equally consistent with either hypothesis".
  If Ada is only a tiny bit better, it will take a large N
to prove conclusively that tiny difference is real.  But who
would care?  OTOH, if Ada is a lot better, it would be both
more important and easier to prove.  I'd sure like a stronger
endorsement than "once we managed to find some Ada experts,
and built some tools, we found Ada modestly better than ...".