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

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 |

R_{0} | solution confined in the interval (0,1) |

R^{–1}(t) | inverse reliability function |

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

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 |