The Expected Fault Group Size metric, which appears in the HTML Fault Group Size Percentages section of the Fault Isolation Report, represents the expected number of replaceable items in fault groups isolated by the diagnostic sequence within the current diagnostic study. This probability-weighted metric reflects the expected number of replacements per isolation if the current diagnostics were to be coupled with a block replacement maintenance strategy.
Alternatively, this Test limit can be calculated by summing the products of the Test limits in fault group Size and % columns (under the Isolation Probabilitites Using Testing Only label) for each row in the Fault Group Size Statistics table. To simplify the equation (shown below), this can be calculated using all sizes up to and including the maximum isolated fault group size:
