Complete the following steps to enter your data. For more information on censored data, go to Data censoring.

- In Start time, enter the column that contains the start times for each interval. The time values in the column depend on how the data are censored.
Observation Value in Start column Exact failure time Failure time Right censored The time the unit is known to have survived to Interval censored The time at the start of the interval during which the failure occurred - In End time, enter the column that contains the end times for each interval. The time values in the column depend on how the data are censored.
Observation Value in End column Exact failure time Failure time Right censored * (missing value symbol) Interval censored The time at the end of the interval during which the failure occurred - If you have frequency data, in Frequency (optional), enter a column that indicates the number of units for each interval.

In this worksheet, the Start column contains the start times of each interval. The End column contains the end times of each interval. The Frequency column (optional) indicates the number of units that are included in each interval. For example, 2 units are exact failures at 30,000 hours. 26 units are interval censored between 30,000 and 40,000 hours. 190 units are right censored at 60,000 hours.

C1 | C2 | C3 |
---|---|---|

Start | End | Frequency |

0 | 10000 | 3 |

10000 | 20000 | 5 |

20000 | 30000 | 10 |

30000 | 30000 | 2 |

30000 | 40000 | 26 |

40000 | 50000 | 40 |

50000 | 60000 | 55 |

60000 | * | 190 |

The same data could also be recorded in the worksheet without a frequency column. In that case, each unit is recorded in a separate row of the worksheet. The number of rows for each interval equals the value in the frequency column. For example, the following worksheet shows how the first 8 rows would appear for these data without a frequency column. The first 3 rows contain each unit that has a start time of 0 and end time of 10,000 hours. The next 5 rows contain each unit that has a start time of 10,000 and end time of 20,000, and so on.

C1 | C2 |
---|---|

Start | End |

0 | 10000 |

0 | 10000 |

0 | 10000 |

10000 | 20000 |

10000 | 20000 |

10000 | 20000 |

10000 | 20000 |

10000 | 20000 |

Select a distribution to model your data. Base your decision on process knowledge or use probability plots to evaluate the model fit. For more information, go to Distribution fit for reliability analysis.

You can enter additional information to have Minitab evaluate the warranty data in relation to the time limits and the costs of the warranty.

- Length of warranty: (optional)
- Enter the length of the warranty for the system. The units of this time value must be the same as those used in the transformed warranty data. Minitab uses this value for the Predicted Number of Failures Plot.
- Average cost per failure: (optional)
- Enter the average cost of a failure. Minitab uses this value to create a Predicted Cost of Failures Plot.