15. The device of claim 14 wherein the confidence indicator is calculated in accordance with: 
 confidence, c ij =1− p ij (1− p ij )/{α(log N ij )} where, p ij =prior probability of test T j failing when component B i is bad N ij =number of observations involving T j and B i , and α=a constant to normalize variance between 0 and 1.
15. The device of claim 14 wherein the confidence indicator is calculated in accordance with: 
 confidence, c ij =1− p ij (1− p ij )/{α(log N ij )} where, p ij =prior probability of test T j failing when component B i is bad N ij =number of observations involving T j and B i , and α=a constant to normalize variance between 0 and 1. 17. The device of claim 15 and wherein generating a cumulative confidence indicator for multiple per-diagnosis confidence intervals includes generating a cumulative confidence indicator, wherein individual confidences are weighted with probabilities.