[ig06]

Thanks for the reply. I had appreciated this problem with my proposed method. Indeed if Alice knows the average weighting she can just tell Bob that is the weighting for all the coins. This spells disaster because the variance is large and the number of heads observed will usually be close to the predicted number.In these contracts there would be a number of other attributes enabling this measure to be computed for different subsets of the data and this was my initial idea to address this problem. However this runs into problems:
- the subsets would have much less data in them
- its not clear how to choose these subsets if there are many parameters.
-I'm sure there are other problems.

I think your betting algorithm is very clever and I will have a think about this. Thanks again