Presentation Profile
Why 30 Points for SQC?
Currently Scheduled: 10/14/2025 - 12:45 PM - 1:30 PM
Room: Tulip
Main Author
Alex Lau - Baytek
Abstract:
This brief seminar will provide a simple overview on the concept of ‘degrees of freedom (df)’ for the standard deviation statistic s , how df can be combined (pooled) from multiple s statistics, and why a minimum df of 30 is specified for repeatability (r) and reproducibility (R) statistics in ASTM D6300 (Standard Practice for Determination of Precision and Bias Data for Use in Test Methods for Petroleum Products and Lubricants).
