For the latest version of JMP Help, visit JMP.com/help.


Design of Experiments Guide > Constant Stress Accelerated Life Test Designs > Statistical Details for the Constant Stress ALT Design Platform > R Precision Factor (for a 95% CI)
Publication date: 07/24/2024

R Precision Factor (for a 95% CI)

The R precision factor for an accelerated life test is a measure of the precision of the estimate of tp, the pth quantile of the failure time distribution. An approximate 95% confidence interval for log(tp) is:

Equation shown here

resulting in a confidence interval for tp;

Equation shown here

where

Equation shown here

To obtain R, use the large sample approximation of the variance of the log(tp):

Equation shown here

Want more information? Have questions? Get answers in the JMP User Community (community.jmp.com).