Methods and formulas for substantiation testing in Demonstration Test Plan

In This Topic

Testing time
Sample size

Testing time

The testing time for each system when the minimum number, N, of components to be tested to substantiate that the redesigned system has significantly improved, at a confidence level of 100(1 – α)%, is calculated as follows:

When m = 0 (0-failure test plan)
When m > 0 (m-failure test plan)
Solve the equation for R (see the "Equation" section in Methods and formulas for M-failure test plan in Demonstration Test Plan. Then obtain t as

Notation

Term	Description
t	time
m	number of failures
α	the significance level (alpha), which equals 1 – confidence level
N	minimum number of components to be tested
R₀	solution confined in the interval (0,1)
R^–1(t)	inverse reliability function

Sample size

The minimum number of systems to be tested to substantiate that the redesigned system has significantly improved, at a confidence level of 100(1 – α)%, is calculated as follows:

When m = 0 (0-failure test plan)
When m > 0 (m-failure test plan)
Solve the equation for N (see the "Equation" section in Methods and formulas for M-failure test plan in Demonstration Test Plan. As a starting value use:

where

Notation

Term	Description
t	time
m	number of failures
α	the significance level (alpha), which equals 1 – confidence level
N	minimum number of systems to be tested
R(t)	reliability function
R^–1(t)	inverse reliability function