I need your help with another problem... I would really appreciate it.

During a circumstancial process, n evidences with probatory value of 2% each are considered.

1) evaluate the probability P1 of guilty on the base of n=1 evidence

2) evaluate P10 of guiltyness on the base of n=10 evidences

3) calculate the minimal number N of evidences such that the probability of guiltyness exceeds 90%.

sorry for my bad English too...

Thanks a lot.