PROBFAIL

Description: Returns the probability of failure or conditional probability of failure at the specified time. For standard probability, enter the end time in the Age field. For conditional probability of failure, enter the start time in the Age field and the additional mission time in the Add Time field.

Syntax: PROBFAIL(Data_Src, Age, [Add Time], [Confidence Level])

Data_Src is the source data sheet from which the value is taken.

Age is either the mission end time for a standard probability calculation, or the start time for a conditional probability calculation.
Add Time is the additional operating time duration. It is only used for conditional calculations.

Confidence Level is the percentage (entered as a decimal value) for the 1-sided confidence bounds.

Remarks:

The Data_Src can be one of the following values:

If using a default data source, it must be either 1, 2, 3 or 4, as selected from the Data Source Index drop-down list.
It can take a data sheet name (e.g., "Folio1!Data 1").
It can take a variable name defined in the Defined Names window (e.g., datasource).

Add Time is an optional value and is only used for conditional calculations. When Add Time is not specified, the probability of failure is calculated for Age. When Add Time is specified, Age is the current age of the item and Add Time is the additional time (or mission time) for which the probability of failure is to be calculated.
Confidence Level is an optional value and, if specified, must be greater than 0 and less than 1.

Example:

PROBFAIL("Folio1!Data 1", 5, 1, 0.1) = 0.3421

Note that this value will vary depending on the source data set.