Confidence Limit

Kenexis
Confidence Interval Estimation Worksheet
Project:
Client:
Device Description:
Manufacturer:
Model:

Inputs:
Number of Failures
Operating Time
Number of Devices
Confidence Interval

0
10
10
70%

Years
per IEC 61508

Outputs:
Total Operating Experience
Total Operating Experience
Mean Failure Rate
MTTF (Mean 50% Conf.)
Degrees of Freedom
Chi-squared
Failure Rate (Confidence)
MTTF (Confidence)
MTTF (Confidence)

100
8.76E+05
1.14E-06
100

Years
Hours
Per Hour
Years

2
2.41
1.37E-06
727591
83.1

per Hour
Hours
Years