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CRE · Question #103

Fifteen(15) motors were tested for a total of 1,200 cumulative hours, with four failure occuring. The test was then failure-truncated. If the failure rate is assumed to be constant, what is the 95%…

The correct answer is B. 155 hours. See the full explanation below for the reasoning.

Data Collection and Use

Question

Fifteen(15) motors were tested for a total of 1,200 cumulative hours, with four failure occuring. The test was then failure-truncated. If the failure rate is assumed to be constant, what is the 95% lower confidence limit of MTBF?

Options

  • A131 hours.
  • B155 hours.
  • C609 hours
  • D876 hours.

How the community answered

(54 responses)
  • A
    4% (2)
  • B
    76% (41)
  • C
    6% (3)
  • D
    15% (8)

Topics

#MTBF#confidence interval#failure-truncated test#chi-square distribution

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