The FAA has updated its advisory circular (AC) offering guidance on the use of statistics in comparative tests during the repair, replacement or redesign of turbine engines and APUs.
Such statistics are often used for analysis when evaluating part dimensions, tolerances or material properties.
AC 33-10 describes “statistical analysis principles which provide acceptable and meaningful results” to ensure compliance with FAA requirements.
The AC also describes a practical alternative approach for statistically-derived sample size requirements.
AC-33-10 can be downloaded from faa.gov (PDF).