Which three life stages does the bathtub curve illustrate?

Which three life stages does the bathtub curve illustrate?

• A. Early-life failures, constant rate during useful life, wear-out failures.
• B. Constant high rate, rapid decline, stabilization.
• C. Only initial failures.
• D. Only wear-out failures.

Answer: (A)

The bathtub curve shows three stages of reliability over time. First, early-life failures occur as defective units fail and are weeded out, so the failure rate drops quickly. Then there’s a period during the useful life where the failure rate is roughly constant, meaning failures happen at a steady, random rate. Finally, as components wear out, the failure rate increases again in the wear-out phase. This combination of early-life failures, a steady-use period, and wear-out failures is what the option describes. Other descriptions miss one or more of these phases or invert the pattern, so they don’t fit the overall curve.

The bathtub curve shows three stages of reliability over time. First, early-life failures occur as defective units fail and are weeded out, so the failure rate drops quickly. Then there’s a period during the useful life where the failure rate is roughly constant, meaning failures happen at a steady, random rate. Finally, as components wear out, the failure rate increases again in the wear-out phase. This combination of early-life failures, a steady-use period, and wear-out failures is what the option describes. Other descriptions miss one or more of these phases or invert the pattern, so they don’t fit the overall curve.