MTBF

For reliability growth data analysis only.

Description: Returns the cumulative or instantaneous MTBF for a given time.

Syntax: MTBF(Data_Src, Time, Type, [Conf_Level])

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

• Time is the time at which the value is calculated.

• Type allows you to select whether to calculate the cumulative or instantaneous MTBF.

• Conf_Level is the percentage (entered as a decimal value) for the confidence bounds. It is an optional value and, if specified, must be greater than 0 and less than 1.

Remarks:

• The Data_Src can be one of the following values:

  • A default data source selected from the Data Source Index drop-down list.

  • A data sheet name (e.g., "Weibull!Folio1!Data1").

  • A variable name defined in the Defined Names window (e.g., datasource).

• The Time value must be greater than 0.

• Cumulative is shown in the function as a numerical value that indicates the selected calculation; for cumulative failure MTBF, Type = 1; for instantaneous MTBF, Type = 0.

Example:

• MTBF("RGA!Folio1!Data1",1000,1,0.8)