15. Precision and Bias (Procedures A, B, and C)
15.1 Precision:
15.1.1 Tables 5 and 6 are based on a round robin4 conducted
in 1986 and 1987, involving polypropylene, polyethylene,
polystyrene, polycarbonate and acrylic materials. Tables 7 and
8 are based on a round robin5 completed in 1997 involving low
and high density polyethylene, polypropylene, polystyrene,
polycarbonate, PMMA, and acetal. The number of participating
laboratories is shown for each material. Data for Tables 5
and 6 were generated through each lab testing two specimens
for each material on three different days, while data for Tables
7 and 8 were generated through each lab testing two specimens
for each material on two different days. The analysis in Practice
E691 is based on a test result being the average of two
specimens.