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Isolation Probabilities Using Testing Only - % Column

Description

This column is listed under the Isolation Probabilities Using Testing Only label in the Fault Group Size Percentages section of the Fault Isolation Report. Each entry in this column contains the probability that the given diagnostic sequence will isolate to a fault group containing the number of replaceable items indicated in the corresponding row in the Size column.

Calculation

This Test limit can be calculated by summing the aggregate failure probabilities associated with each isolated fault groups of the given size and then dividing the sum by the Total Probability Detected, as shown in the following equation:

where

x	=	the specified number of replacement items (Size column)
N	=	the total number of isolated fault groups (Total Fault Groups)
FG_i	=	the ith isolated fault group
X_i	=	1 if FG_i contains x replacement items; 0 otherwise
Afp(FG_i)	=	the aggregate failure probability associated with FG_i
DetPr	=	the Total Probability Detected

Note: Because fault isolation statistics are calculated over the set of detected failures, the Test limits in this column will add up to 100.00 even when the Total Probability Detected is less than 100.00 for the diagnostic sequence generated in the current diagnostic study.

Standards, Handbooks and Publications

The following Standards, Handbooks and Publications provide information about this and/or similar metrics:

Metric	Standard
Incremental Expected Percentage of Isolation	IEEE 1522 (2004)
Percent Fault Isolation	Joint Forces Memo (2003)
Percent isolation to a single RI	MIL-HDBK-472 (1984)